Compact Layers of Hybrid Halide Perovskites Fabricated via the Aerosol Deposition Process-Uncoupling Material Synthesis and Layer Formation.

PubMed

Panzer, Fabian; Hanft, Dominik; Gujar, Tanaji P; Kahle, Frank-Julian; Thelakkat, Mukundan; Köhler, Anna; Moos, Ralf

2016-04-08

We present the successful fabrication of CH₃NH₃PbI₃ perovskite layers by the aerosol deposition method (ADM). The layers show high structural purity and compactness, thus making them suitable for application in perovskite-based optoelectronic devices. By using the aerosol deposition method we are able to decouple material synthesis from layer processing. Our results therefore allow for enhanced and easy control over the fabrication of perovskite-based devices, further paving the way for their commercialization.

Long life hydrocarbon conversion catalyst and method of making

DOEpatents

Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

2002-11-12

The present invention includes a catalyst that has at least four layers, (1) porous support, (2) buffer layer, (3) interfacial layer, and optionally (4) catalyst layer. The buffer layer provides a transition of thermal expansion coefficient from the porous support to the interfacial layer thereby reducing thermal expansion stress as the catalyst is heated to high operating temperatures. The method of the present invention for making the at least three layer catalyst has the steps of (1) selecting a porous support, (2) solution depositing an interfacial layer thereon, and optionally (3) depositing a catalyst material onto the interfacial layer; wherein the improvement comprises (4) depositing a buffer layer between the porous support and the interfacial layer.

Method for depositing layers of high quality semiconductor material

DOEpatents

Guha, Subhendu; Yang, Chi C.

2001-08-14

Plasma deposition of substantially amorphous semiconductor materials is carried out under a set of deposition parameters which are selected so that the process operates near the amorphous/microcrystalline threshold. This threshold varies as a function of the thickness of the depositing semiconductor layer; and, deposition parameters, such as diluent gas concentrations, must be adjusted as a function of layer thickness. Also, this threshold varies as a function of the composition of the depositing layer, and in those instances where the layer composition is profiled throughout its thickness, deposition parameters must be adjusted accordingly so as to maintain the amorphous/microcrystalline threshold.

Organic electronic devices with multiple solution-processed layers

DOEpatents

Forrest, Stephen R.; Lassiter, Brian E.; Zimmerman, Jeramy D.

2015-08-04

A method of fabricating a tandem organic photosensitive device involves depositing a first layer of an organic electron donor type material film by solution-processing of the organic electron donor type material dissolved in a first solvent; depositing a first layer of an organic electron acceptor type material over the first layer of the organic electron donor type material film by a dry deposition process; depositing a conductive layer over the interim stack by a dry deposition process; depositing a second layer of the organic electron donor type material over the conductive layer by solution-processing of the organic electron donor type material dissolved in a second solvent, wherein the organic electron acceptor type material and the conductive layer are insoluble in the second solvent; depositing a second layer of an organic electron acceptor type material over the second layer of the organic electron donor type material film by a dry deposition process, resulting in a stack.

Surface control alloy substrates and methods of manufacture therefor

DOEpatents

Fritzemeier, Leslie G.; Li, Qi; Rupich, Martin W.; Thompson, Elliott D.; Siegal, Edward J.; Thieme, Cornelis Leo Hans; Annavarapu, Suresh; Arendt, Paul N.; Foltyn, Stephen R.

2004-05-04

Methods and articles for controlling the surface of an alloy substrate for deposition of an epitaxial layer. The invention includes the use of an intermediate layer to stabilize the substrate surface against oxidation for subsequent deposition of an epitaxial layer.

Methods of fabrication of graphene nanoribbons

DOEpatents

Zhang, Yuegang

2015-06-23

Methods of fabricating graphene nanoribbons include depositing a catalyst layer on a substrate. A masking layer is deposited on the catalyst layer. The masking layer and the catalyst layer are etched to form a structure on the substrate, the structure comprising a portion of the catalyst layer and a portion of the masking layer disposed on the catalyst layer, with sidewalls of the catalyst layer being exposed. A graphene layer is formed on a sidewall of the catalyst layer with a carbon-containing gas.

Buffer architecture for biaxially textured structures and method of fabricating same

DOEpatents

Norton, David P.; Park, Chan; Goyal, Amit

2004-04-06

The invention relates to an article with an improved buffer layer architecture comprising a substrate having a metal surface, and an epitaxial buffer layer on the surface of the substrate. The epitaxial buffer layer comprises at least one of the group consisting of ZrO.sub.2, HfO.sub.2, and compounds having at least one of Ca and a rare earth element stabilizing cubic phases of ZrO.sub.2 and/or HfO.sub.2. The article can also include a superconducting layer deposited on the epitaxial buffer layer. The article can also include an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article comprises providing a substrate with a metal surface, depositing on the metal surface an epitaxial buffer layer comprising at least one material selected from the group consisting of ZrO.sub.2, HfO.sub.2, and compounds having at least one of Ca and a rare earth element stabilizing cubic phases of at least one of ZrO.sub.2 and HfO.sub.2. The epitaxial layer depositing step occurs in a vacuum with a background pressure of no more than 1.times.10.sup.-5 Torr. The method can further comprise depositing a superconducting layer on the epitaxial layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

Method for ultra-fast boriding

DOEpatents

Erdemir, Ali; Sista, Vivekanand; Kahvecioglu, Ozgenur; Eryilmaz, Osman Levent

2017-01-31

An article of manufacture and method of forming a borided material. An electrochemical cell is used to process a substrate to deposit a plurality of borided layers on the substrate. The plurality of layers are co-deposited such that a refractory metal boride layer is disposed on a substrate and a rare earth metal boride conforming layer is disposed on the refractory metal boride layer.

Electrolytic etch for preventing electrical shorts in solar cells on polymer surfaces

DOEpatents

Weber, Michael F.

1991-10-08

A method for preventing shorts and shunts in solar cells having in order, an insulating substrate, a conductive metal layer on the substrate, an amorphous silicon layer and a transparent conductive layer. The method includes anodic etching of exposed portions of the metal layer after deposition of the amorphous silicon and prior to depositing the transparent conductive layer.

Conformal coating of highly structured surfaces

DOEpatents

Ginley, David S.; Perkins, John; Berry, Joseph; Gennett, Thomas

2012-12-11

Method of applying a conformal coating to a highly structured substrate and devices made by the disclosed methods are disclosed. An example method includes the deposition of a substantially contiguous layer of a material upon a highly structured surface within a deposition process chamber. The highly structured surface may be associated with a substrate or another layer deposited on a substrate. The method includes depositing a material having an amorphous structure on the highly structured surface at a deposition pressure of equal to or less than about 3 mTorr. The method may also include removing a portion of the amorphous material deposited on selected surfaces and depositing additional amorphous material on the highly structured surface.

Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

NASA Astrophysics Data System (ADS)

Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

2015-11-01

Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

Novel Solvent-free Perovskite Deposition in Fabrication of Normal and Inverted Architectures of Perovskite Solar Cells

PubMed Central

Nejand, Bahram Abdollahi; Gharibzadeh, Saba; Ahmadi, Vahid; Shahverdi, H. Reza

2016-01-01

We introduced a new approach to deposit perovskite layer with no need for dissolving perovskite precursors. Deposition of Solution-free perovskite (SFP) layer is a key method for deposition of perovskite layer on the hole or electron transport layers that are strongly sensitive to perovskite precursors. Using deposition of SFP layer in the perovskite solar cells would extend possibility of using many electron and hole transport materials in both normal and invert architectures of perovskite solar cells. In the present work, we synthesized crystalline perovskite powder followed by successful deposition on TiO2 and cuprous iodide as the non-sensitve and sensitive charge transport layers to PbI2 and CH3NH3I solution in DMF. The post compressing step enhanced the efficiency of the devices by increasing the interface area between perovskite and charge transport layers. The 9.07% and 7.71% cell efficiencies of the device prepared by SFP layer was achieved in respective normal (using TiO2 as a deposition substrate) and inverted structure (using CuI as deposition substrate) of perovskite solar cell. This method can be efficient in large-scale and low cost fabrication of new generation perovskite solar cells. PMID:27640991

Thin-film solar cell fabricated on a flexible metallic substrate

DOEpatents

Tuttle, John R.; Noufi, Rommel; Hasoon, Falah S.

2006-05-30

A thin-film solar cell (10) is provided. The thin-film solar cell (10) comprises a flexible metallic substrate (12) having a first surface and a second surface. A back metal contact layer (16) is deposited on the first surface of the flexible metallic substrate (12). A semiconductor absorber layer (14) is deposited on the back metal contact. A photoactive film deposited on the semiconductor absorber layer (14) forms a heterojunction structure and a grid contact (24) deposited on the heterjunction structure. The flexible metal substrate (12) can be constructed of either aluminium or stainless steel. Furthermore, a method of constructing a solar cell is provided. The method comprises providing an aluminum substrate (12), depositing a semiconductor absorber layer (14) on the aluminum substrate (12), and insulating the aluminum substrate (12) from the semiconductor absorber layer (14) to inhibit reaction between the aluminum substrate (12) and the semiconductor absorber layer (14).

Thin-Film Solar Cell Fabricated on a Flexible Metallic Substrate

DOEpatents

Tuttle, J. R.; Noufi, R.; Hasoon, F. S.

2006-05-30

A thin-film solar cell (10) is provided. The thin-film solar cell (10) comprises a flexible metallic substrate (12) having a first surface and a second surface. A back metal contact layer (16) is deposited on the first surface of the flexible metallic substrate (12). A semiconductor absorber layer (14) is deposited on the back metal contact. A photoactive film deposited on the semiconductor absorber layer (14) forms a heterojunction structure and a grid contact (24) deposited on the heterjunction structure. The flexible metal substrate (12) can be constructed of either aluminium or stainless steel. Furthermore, a method of constructing a solar cell is provided. The method comprises providing an aluminum substrate (12), depositing a semiconductor absorber layer (14) on the aluminum substrate (12), and insulating the aluminum substrate (12) from the semiconductor absorber layer (14) to inhibit reaction between the aluminum substrate (12) and the semiconductor absorber layer (14).

Method of deposition by molecular beam epitaxy

DOEpatents

Chalmers, Scott A.; Killeen, Kevin P.; Lear, Kevin L.

1995-01-01

A method is described for reproducibly controlling layer thickness and varying layer composition in an MBE deposition process. In particular, the present invention includes epitaxially depositing a plurality of layers of material on a substrate with a plurality of growth cycles whereby the average of the instantaneous growth rates for each growth cycle and from one growth cycle to the next remains substantially constant as a function of time.

Method of deposition by molecular beam epitaxy

DOEpatents

Chalmers, S.A.; Killeen, K.P.; Lear, K.L.

1995-01-10

A method is described for reproducibly controlling layer thickness and varying layer composition in an MBE deposition process. In particular, the present invention includes epitaxially depositing a plurality of layers of material on a substrate with a plurality of growth cycles whereby the average of the instantaneous growth rates for each growth cycle and from one growth cycle to the next remains substantially constant as a function of time. 9 figures.

Use of inverse quasi-epitaxy to modify order during post-deposition processing of organic photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forrest, Stephen R.; Zimmerman, Jeramy D.; Lassiter, Brian E .

Disclosed herein are methods for fabricating an organic photovoltaic device comprising depositing an amorphous organic layer and a crystalline organic layer over a first electrode, wherein the amorphous organic layer and the crystalline organic layer contact one another at an interface; annealing the amorphous organic layer and the crystalline organic layer for a time sufficient to induce at least partial crystallinity in the amorphous organic layer; and depositing a second electrode over the amorphous organic layer and the crystalline organic layer. In the methods and devices herein, the amorphous organic layer may comprise at least one material that undergoes inverse-quasimore » epitaxial (IQE) alignment to a material of the crystalline organic layer as a result of the annealing.« less

Layer-by-layer deposition of nanostructured CsPbBr3 perovskite thin films

NASA Astrophysics Data System (ADS)

Reshetnikova, A. A.; Matyushkin, L. B.; Andronov, A. A.; Sokolov, V. S.; Aleksandrova, O. A.; Moshnikov, V. A.

2017-11-01

Layer-by-layer deposition of nanostructured perovskites cesium lead halide thin films is described. The method of deposition is based on alternate immersion of the substrate in the precursor solutions or colloidal solution of nanocrystals and methyl acetate/lead nitrate solution using the device for deposition of films by SILAR and dip-coating techniques. An example of obtaining a photosensitive structure based on nanostructures of ZnO nanowires and layers of CsBbBr3 nanocrystals is also shown.

Controlled placement and orientation of nanostructures

DOEpatents

Zettl, Alex K; Yuzvinsky, Thomas D; Fennimore, Adam M

2014-04-08

A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Method of making diode structures

DOEpatents

Compaan, Alvin D.; Gupta, Akhlesh

2006-11-28

A method of making a diode structure includes the step of depositing a transparent electrode layer of any one or more of the group ZnO, ZnS and CdO onto a substrate layer, and depositing an active semiconductor junction having an n-type layer and a p-type layer onto the transparent electrode layer under process conditions that avoid substantial degradation of the electrode layer. A back electrode coating layer is applied to form a diode structure.

Method of adhesion between an oxide layer and a metal layer

DOEpatents

Jennison, Dwight R.; Bogicevic, Alexander; Kelber, Jeffry A.; Chambers, Scott A.

2004-09-14

A method of controlling the wetting characteristics and increasing the adhesion between a metal and an oxide layer. By introducing a negatively-charged species to the surface of an oxide layer, layer-by-layer growth of metal deposited onto the oxide surface is promoted, increasing the adhesion strength of the metal-oxide interface. The negatively-charged species can either be deposited onto the oxide surface or a compound can be deposited that dissociates on, or reacts with, the surface to form the negatively-charged species. The deposited metal adatoms can thereby bond laterally to the negatively-charged species as well as vertically to the oxide surface as well as react with the negatively charged species, be oxidized, and incorporated on or into the surface of the oxide.

Depth Profiling Analysis of Aluminum Oxidation During Film Deposition in a Conventional High Vacuum System

NASA Technical Reports Server (NTRS)

Kim, Jongmin; Weimer, Jeffrey J.; Zukic, Muamer; Torr, Douglas G.

1994-01-01

The oxidation of aluminum thin films deposited in a conventional high vacuum chamber has been investigated using x-ray photoelectron spectroscopy (XPS) and depth profiling. The state of the Al layer was preserved by coating it with a protective MgF2 layer in the deposition chamber. Oxygen concentrations in the film layers were determined as a function of sputter time (depth into the film). The results show that an oxidized layer is formed at the start of Al deposition and that a less extensively oxidized Al layer is deposited if the deposition rate is fast. The top surface of the Al layer oxidizes very quickly. This top oxidized layer may be thicker than has been previously reported by optical methods. Maximum oxygen concentrations measured by XPS at each Al interface are related to pressure to rate ratios determined during the Al layer deposition.

High power RF window deposition apparatus, method, and device

DOEpatents

Ives, Lawrence R.; Lucovsky, Gerald; Zeller, Daniel

2017-07-04

A process for forming a coating for an RF window which has improved secondary electron emission and reduced multipactor for high power RF waveguides is formed from a substrate with low loss tangent and desirable mechanical characteristics. The substrate has an RPAO deposition layer applied which oxygenates the surface of the substrate to remove carbon impurities, thereafter has an RPAN deposition layer applied to nitrogen activate the surface of the substrate, after which a TiN deposition layer is applied using Titanium tert-butoxide. The TiN deposition layer is capped with a final RPAN deposition layer of nitridation to reduce the bound oxygen in the TiN deposition layer. The resulting RF window has greatly improved titanium layer adhesion, reduced multipactor, and is able to withstand greater RF power levels than provided by the prior art.

Fluorine compounds for doping conductive oxide thin films

DOEpatents

Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

2013-04-23

Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods.

PubMed

Park, Sung-Eun; Kim, Sehwan; Kim, Kangmin; Joe, Hang-Eun; Jung, Buyoung; Kim, Eunkyoung; Kim, Woochul; Min, Byung-Kwon; Hwang, Jungho

2012-12-21

Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method. The donor-acceptor interface layer was observed by obtaining cross-sectional images with a focused ion beam (FIB) microscope. The photocurrent generation performance of the OHJ cells was evaluated with the current density-voltage curve under air mass (AM) 1.5 conditions. It was found that the surface morphology of the electron acceptor layer affected the current and voltage outputs of the photovoltaic cells. When an electron acceptor layer with a smooth thin (250 nm above the valley of the electron donor layer) surface morphology was obtained, power conversion efficiency was as high as 0.55%. The electrohydrodynamic spray deposition method used to produce OHJ photovoltaic cells provides a means for the adoption of large area, high throughput processes.

Improving yield and performance in ZnO thin-film transistors made using selective area deposition.

PubMed

Nelson, Shelby F; Ellinger, Carolyn R; Levy, David H

2015-02-04

We describe improvements in both yield and performance for thin-film transistors (TFTs) fabricated by spatial atomic layer deposition (SALD). These improvements are shown to be critical in forming high-quality devices using selective area deposition (SAD) as the patterning method. Selective area deposition occurs when the precursors for the deposition are prevented from reacting with some areas of the substrate surface. Controlling individual layer quality and the interfaces between layers is essential for obtaining good-quality thin-film transistors and capacitors. The integrity of the gate insulator layer is particularly critical, and we describe a method for forming a multilayer dielectric using an oxygen plasma treatment between layers that improves crossover yield. We also describe a method to achieve improved mobility at the important interface between the semiconductor and the gate insulator by, conversely, avoiding oxygen plasma treatment. Integration of the best designs results in wide design flexibility, transistors with mobility above 15 cm(2)/(V s), and good yield of circuits.

Method of forming a multiple layer dielectric and a hot film sensor therewith

NASA Technical Reports Server (NTRS)

Hopson, Purnell, Jr. (Inventor); Tran, Sang Q. (Inventor)

1990-01-01

The invention is a method of forming a multiple layer dielectric for use in a hot-film laminar separation sensor. The multiple layer dielectric substrate is formed by depositing a first layer of a thermoelastic polymer such as on an electrically conductive substrate such as the metal surface of a model to be tested under cryogenic conditions and high Reynolds numbers. Next, a second dielectric layer of fused silica is formed on the first dielectric layer of thermoplastic polymer. A resistive metal film is deposited on selected areas of the multiple layer dielectric substrate to form one or more hot-film sensor elements to which aluminum electrical circuits deposited upon the multiple layered dielectric substrate are connected.

Conductive layer for biaxially oriented semiconductor film growth

DOEpatents

Findikoglu, Alp T.; Matias, Vladimir

2007-10-30

A conductive layer for biaxially oriented semiconductor film growth and a thin film semiconductor structure such as, for example, a photodetector, a photovoltaic cell, or a light emitting diode (LED) that includes a crystallographically oriented semiconducting film disposed on the conductive layer. The thin film semiconductor structure includes: a substrate; a first electrode deposited on the substrate; and a semiconducting layer epitaxially deposited on the first electrode. The first electrode includes a template layer deposited on the substrate and a buffer layer epitaxially deposited on the template layer. The template layer includes a first metal nitride that is electrically conductive and has a rock salt crystal structure, and the buffer layer includes a second metal nitride that is electrically conductive. The semiconducting layer is epitaxially deposited on the buffer layer. A method of making such a thin film semiconductor structure is also described.

Metallic coatings on silicon substrates, and methods of forming metallic coatings on silicon substrates

DOEpatents

Branagan, Daniel J [Idaho Falls, ID; Hyde, Timothy A [Idaho Falls, ID; Fincke, James R [Los Alamos, NM

2008-03-11

The invention includes methods of forming a metallic coating on a substrate which contains silicon. A metallic glass layer is formed over a silicon surface of the substrate. The invention includes methods of protecting a silicon substrate. The substrate is provided within a deposition chamber along with a deposition target. Material from the deposition target is deposited over at least a portion of the silicon substrate to form a protective layer or structure which contains metallic glass. The metallic glass comprises iron and one or more of B, Si, P and C. The invention includes structures which have a substrate containing silicon and a metallic layer over the substrate. The metallic layer contains less than or equal to about 2 weight % carbon and has a hardness of at least 9.2 GPa. The metallic layer can have an amorphous microstructure or can be devitrified to have a nanocrystalline microstructure.

Method for producing high energy electroluminescent devices

DOEpatents

Meyerson, Bernard S.; Scott, Bruce A.; Wolford, Jr., Donald J.

1992-09-29

A method is described for fabricating electroluminescent devices exhibiting visible electroluminescence at room temperature, where the devices include at least one doped layer of amorphous hydrogenated silicon (a-Si:H). The a-Si:H layer is deposited on a substrate by homogeneous chemical vapor deposition (H-CVD) in which the substrate is held at a temperature lower than about 200.degree. C. and the a-Si:H layer is doped in-situ during deposition, the amount of hydrogen incorporated in the deposited layer being 12-50 atomic percent. The bandgap of the a-Si:H layer is between 1.6 and 2.6 eV, and in preferrable embodiments is between 2.0 and 2.6 eV. The conductivity of the a-Si:H layer is chosen in accordance with device requirements, and can be 10.sup.16 -10.sup.19 carriers/cm.sup.2. The bandgap of the a-Si:H layer depends at least in part on the temperature of the substrate on which the layer is deposited, and can be "tuned" by changing the substrate temperature.

The optical properties of transferred graphene and the dielectrics grown on it obtained by ellipsometry

NASA Astrophysics Data System (ADS)

Kasikov, Aarne; Kahro, Tauno; Matisen, Leonard; Kodu, Margus; Tarre, Aivar; Seemen, Helina; Alles, Harry

2018-04-01

Graphene layers grown by chemical vapour deposition (CVD) method and transferred from Cu-foils to the oxidized Si-substrates were investigated by spectroscopic ellipsometry (SE), Raman and X-Ray Photoelectron Spectroscopy (XPS) methods. The optical properties of transferred CVD graphene layers do not always correspond to the ones of the exfoliated graphene due to the contamination from the chemicals used in the transfer process. However, the real thickness and the mean properties of the transferred CVD graphene layers can be found using ellipsometry if a real thickness of the SiO2 layer is taken into account. The pulsed laser deposition (PLD) and atomic layer deposition (ALD) methods were used to grow dielectric layers on the transferred graphene and the obtained structures were characterized using optical methods. The approach demonstrated in this work could be useful for the characterization of various materials grown on graphene.

Underpotential deposition-mediated layer-by-layer growth of thin films

DOEpatents

Wang, Jia Xu; Adzic, Radoslav R.

2015-05-19

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves the use of underpotential deposition of a first element to mediate the growth of a second material by overpotential deposition. Deposition occurs between a potential positive to the bulk deposition potential for the mediating element where a full monolayer of mediating element forms, and a potential which is less than, or only slightly greater than, the bulk deposition potential of the material to be deposited. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis. This process is especially suitable for the formation of a catalytically active layer on core-shell particles for use in energy conversion devices such as fuel cells.

Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Wonjong; Cho, Gu Young; Noh, Seungtak

2015-01-15

An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visiblymore » higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility.« less

Secondary treatment of films of colloidal quantum dots for optoelectronics and devices produced thereby

DOEpatents

Semonin, Octavi Escala; Luther, Joseph M; Beard, Matthew C; Chen, Hsiang-Yu

2014-04-01

A method of forming an optoelectronic device. The method includes providing a deposition surface and contacting the deposition surface with a ligand exchange chemical and contacting the deposition surface with a quantum dot (QD) colloid. This initial process is repeated over one or more cycles to form an initial QD film on the deposition surface. The method further includes subsequently contacting the QD film with a secondary treatment chemical and optionally contacting the surface with additional QDs to form an enhanced QD layer exhibiting multiple exciton generation (MEG) upon absorption of high energy photons by the QD active layer. Devices having an enhanced QD active layer as described above are also disclosed.

Article and method for making an article

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of depositing a metal alloy powder to form an initial layer including at least one aperture, melting the metal alloy powder with a focused energy source to transform the powder layer to a sheet of metal alloy, sequentially depositing an additional layer of the metal alloy powder to form a layer including at least one aperture corresponding to the at least one aperture in the initial layer, melting the additional layer of the metal alloy powder with the focused energymore » source to increase the sheet thickness, and repeating the steps of sequentially depositing and melting the additional layers of metal alloy powder until a structure including at least one aperture having a predetermined profile is obtained. The structure is attached to a substrate to make the article.« less

Method of depositing a high-emissivity layer

DOEpatents

Wickersham, Charles E.; Foster, Ellis L.

1983-01-01

A method of depositing a high-emissivity layer on a substrate comprising RF sputter deposition of a carbide-containing target in an atmosphere of a hydrocarbon gas and a noble gas. As the carbide is deposited on the substrate the hydrocarbon gas decomposes to hydrogen and carbon. The carbon deposits on the target and substrate causing a carbide/carbon composition gradient to form on the substrate. At a sufficiently high partial pressure of hydrocarbon gas, a film of high-emissivity pure carbon will eventually form over the substrate.

Method of transferring a thin crystalline semiconductor layer

DOEpatents

Nastasi, Michael A [Sante Fe, NM; Shao, Lin [Los Alamos, NM; Theodore, N David [Mesa, AZ

2006-12-26

A method for transferring a thin semiconductor layer from one substrate to another substrate involves depositing a thin epitaxial monocrystalline semiconductor layer on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the thin semiconductor layer is bonded to a second substrate and the thin layer is separated away at the interface, which results in transferring the thin epitaxial semiconductor layer from one substrate to the other substrate.

Method of controllong the deposition of hydrogenated amorphous silicon and apparatus therefor

DOEpatents

Hanak, Joseph J.

1985-06-25

An improved method and apparatus for the controlled deposition of a layer of hydrogenated amorphous silicon on a substrate. Means is provided for the illumination of the coated surface of the substrate and measurement of the resulting photovoltage at the outermost layer of the coating. Means is further provided for admixing amounts of p type and n type dopants to the reactant gas in response to the measured photovoltage to achieve a desired level and type of doping of the deposited layer.

Monitoring of Soft Deposition Layers in Liquid-Filled Tubes with Guided Acoustic Waves Excited by Clamp-on Transducers.

PubMed

Tietze, Sabrina; Singer, Ferdinand; Lasota, Sandra; Ebert, Sandra; Landskron, Johannes; Schwuchow, Katrin; Drese, Klaus Stefan; Lindner, Gerhard

2018-02-09

The monitoring of liquid-filled tubes with respect to the formation of soft deposition layers such as biofilms on the inner walls calls for non-invasive and long-term stable sensors, which can be attached to existing pipe structures. For this task a method is developed, which uses an ultrasonic clamp-on device. This method is based on the impact of such deposition layers on the propagation of circumferential guided waves on the pipe wall. Such waves are partly converted into longitudinal compressional waves in the liquid, which are back-converted to guided waves in a circular cross section of the pipe. Validating this approach, laboratory experiments with gelatin deposition layers on steel tubes exhibited a distinguishable sensitivity of both wave branches with respect to the thickness of such layers. This allows the monitoring of the layer growth.

Mitigating leaks in membranes

DOEpatents

Karnik, Rohit N.; Bose, Suman; Boutilier, Michael S.H.; Hadjiconstantinou, Nicolas G.; Jain, Tarun Kumar; O'Hern, Sean C.; Laoui, Tahar; Atieh, Muataz A.; Jang, Doojoon

2018-02-27

Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

Preparation of low-sulfur platinum and platinum aluminide layers in thermal barrier coatings

NASA Technical Reports Server (NTRS)

Spitsberg, Irene T. (Inventor); Walston, William S. (Inventor); Schaeffer, Jon C. (Inventor)

2003-01-01

A method for preparing a coated nickel-base superalloy article reduces the sulfur content of the surface region of the metallic coating layers to low levels, thereby improving the adhesion of the coating layers to the article. The method includes depositing a first layer of platinum overlying the surface of a substrate, depositing a second layer of aluminum over the platinum, and final desulfurizing the article by heating the article to elevated temperature, preferably in hydrogen, and removing a small amount of material from the surface that was exposed during the step of heating. A ceramic layer may be deposited over the desulfurized article. The article may also be similarly desulfurized at other points in the fabrication procedure.

Apparatus and method for intra-layer modulation of the material deposition and assist beam and the multilayer structure produced therefrom

NASA Technical Reports Server (NTRS)

Wadley, Hadyn N. G. (Inventor); Zhou, Xiaowang (Inventor); Quan, Junjie (Inventor)

2002-01-01

A method of producing a multilayer structure that has reduced interfacial roughness and interlayer mixing by using a physical-vapor deposition apparatus. In general the method includes forming a bottom layer having a first material wherein a first plurality of monolayers of the first material is deposited on an underlayer using a low incident adatom energy. Next, a second plurality of monolayers of the first material is deposited on top of the first plurality of monolayers of the first material using a high incident adatom energy. Thereafter, the method further includes forming a second layer having a second material wherein a first plurality of monolayers of the second material is deposited on the second plurality of monolayers of the first material using a low incident adatom energy. Next, a second plurality of monolayers of the second material is deposited on the first plurality of monolayers of the second material using a high incident adatom energy.

Method Producing an SNS Superconducting Junction with Weak Link Barrier

NASA Technical Reports Server (NTRS)

Hunt, Brian D. (Inventor)

1999-01-01

A method of producing a high temperature superconductor Josephson element and an improved SNS weak link barrier element is provided. A YBaCuO superconducting electrode film is deposited on a substrate at a temperature of approximately 800 C. A weak link barrier layer of a nonsuperconducting film of N-YBaCuO is deposited over the electrode at a temperature range of 520 C. to 540 C. at a lower deposition rate. Subsequently a superconducting counter-electrode film layer of YBaCuO is deposited over the weak link barrier layer at approximately 800 C. The weak link barrier layer has a thickness of approximately 50 A and the SNS element can be constructed to provide an edge geometry junction.

Schottky barrier solar cell

NASA Technical Reports Server (NTRS)

Stirn, R. J.; Yeh, Y. C. M. (Inventor)

1981-01-01

A method of fabricating a Schottky barrier solar cell is described. The cell consists of a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive. A thin layer of heavily doped n-type polycrystalling germanium is deposited on the substrate after a passivation layer is deposited to prevent migration of impurities into the polycrystalline germanium. The polycrystalline germanium is recrystallized to increase the crystal sizes to serve as a base layer on which a thin layer of gallium arsenide is vapor-epitaxilly grown followed by a thermally-grown oxide layer. A metal layer is deposited on the oxide layer and a grid electrode is deposited to be in electrical contact with the top surface of the metal layer.

Bulk heterojunction formation between indium tin oxide nanorods and CuInS2 nanoparticles for inorganic thin film solar cell applications.

PubMed

Cho, Jin Woo; Park, Se Jin; Kim, Jaehoon; Kim, Woong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

2012-02-01

In this study, we developed a novel inorganic thin film solar cell configuration in which bulk heterojunction was formed between indium tin oxide (ITO) nanorods and CuInS(2) (CIS). Specifically, ITO nanorods were first synthesized by the radio frequency magnetron sputtering deposition method followed by deposition of a dense TiO(2) layer and CdS buffer layer using atomic layer deposition and chemical bath deposition method, respectively. The spatial region between the nanorods was then filled with CIS nanoparticle ink, which was presynthesized using the colloidal synthetic method. We observed that complete gap filling was achieved to form bulk heterojunction between the inorganic phases. As a proof-of-concept, solar cell devices were fabricated by depositing an Au electrode on top of the CIS layer, which exhibited the best photovoltaic response with a V(oc), J(sc), FF, and efficiency of 0.287 V, 9.63 mA/cm(2), 0.364, and 1.01%, respectively.

Method of manufacturing a shapeable short-resistant capacitor

DOEpatents

Taylor, Ralph S.; Myers, John D.; Baney, William J.

2013-04-02

A method that employs a novel combination of conventional fabrication techniques provides a ceramic short-resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The method allows thinner and more flexible ceramic capacitors to be made. The method includes forming a first thin metal layer on a substrate; depositing a thin, ceramic dielectric layer over the metal layer; depositing a second thin metal layer over the dielectric layer to form a capacitor exhibiting a benign failure mode; and separating the capacitor from the substrate. The method may also include bending the resulting capacitor into a serpentine arrangement with gaps between the layers that allow venting of evaporated electrode material in the event of a benign failure.

Electrical properties of aluminum contacts deposited by DC sputtering method for photovoltaic applications

NASA Astrophysics Data System (ADS)

Krawczak, Ewelina; Gułkowski, Sławomir

2017-10-01

The use of aluminum contacts is common in the process of silicon solar cells production because of low contact resistivity. It has also a great importance in thin film technology for photovoltaics, especially in copper-indium-gallium-diselenide (CIGS) devices. The final stage of CIGS cell production is the top contact deposition of high conductivity layer for lateral current collection. Such material has to be highly optically transparent as well. In order to make a contact, metal is deposited onto TCO layer with minimum shadowing to allow as much light as possible into device. The metal grid contact is being made by deposition of few microns of aluminum. The resistivity of the deposited material as well as resistance between the metal grid and TCO layer plays a great role in high quality solar cell production. This paper presents the results of four point probe conductivity analysis of Al thin films deposited by direct current (DC) magnetron sputtering method. Influence of technological parameters of the Al deposition process on sheet resistance of deposited layers has been showed. In order to obtain the lowest resistivity of the thin contact layer, optimal set of sputtering parameters, i.e. power applied, deposition time and deposition pressure was found. The resistivity of the contact between two adjacent Al metal fingers deposited onto transparent conductive Al-doped zinc oxide film has been also examined.

Elimination of initial stress-induced curvature in a micromachined bi-material composite-layered cantilever

NASA Astrophysics Data System (ADS)

Liu, Ruiwen; Jiao, Binbin; Kong, Yanmei; Li, Zhigang; Shang, Haiping; Lu, Dike; Gao, Chaoqun; Chen, Dapeng

2013-09-01

Micro-devices with a bi-material-cantilever (BMC) commonly suffer initial curvature due to the mismatch of residual stress. Traditional corrective methods to reduce the residual stress mismatch generally involve the development of different material deposition recipes. In this paper, a new method for reducing residual stress mismatch in a BMC is proposed based on various previously developed deposition recipes. An initial material film is deposited using two or more developed deposition recipes. This first film is designed to introduce a stepped stress gradient, which is then balanced by overlapping a second material film on the first and using appropriate deposition recipes to form a nearly stress-balanced structure. A theoretical model is proposed based on both the moment balance principle and total equal strain at the interface of two adjacent layers. Experimental results and analytical models suggest that the proposed method is effective in producing multi-layer micro cantilevers that display balanced residual stresses. The method provides a generic solution to the problem of mismatched initial stresses which universally exists in micro-electro-mechanical systems (MEMS) devices based on a BMC. Moreover, the method can be incorporated into a MEMS design automation package for efficient design of various multiple material layer devices from MEMS material library and developed deposition recipes.

Conductive and robust nitride buffer layers on biaxially textured substrates

DOEpatents

Sankar, Sambasivan [Chicago, IL; Goyal, Amit [Knoxville, TN; Barnett, Scott A [Evanston, IL; Kim, Ilwon [Skokie, IL; Kroeger, Donald M [Knoxville, TN

2009-03-31

The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metals and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layer. In some embodiments the article further comprises electromagnetic devices which may have superconducting properties.

Method for making MgO buffer layers on rolled nickel or copper as superconductor substrates

DOEpatents

Paranthaman, Mariappan; Goyal, Amit; Kroeger, Donald M.; List, III, Frederic A.

2002-01-01

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled-Ni and/or Cu substrates for high current conductors, and more particularly buffer layer architectures such as MgO/Ag/Pt/Ni, MgO/Ag/Pd/Ni, MgO/Ag/Ni, MgO/Ag/Pd/Cu, MgO/Ag/Pt/Cu, and MgO/Ag/Cu. Techniques used to deposit these buffer layers include electron beam evaporation, thermal evaporation, rf magnetron sputtering, pulsed laser deposition, metal-organic chemical vapor deposition (MOCVD), combustion CVD, and spray pyrolysis.

Method of Fabricating Schottky Barrier solar cell

NASA Technical Reports Server (NTRS)

Stirn, R. J.; Yeh, Y. C. M. (Inventor)

1982-01-01

On a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive is deposited a thin layer of heavily doped n-type polycrystalline germanium, with crystalline sizes in the submicron range. A passivation layer may be deposited on the substrate to prevent migration of impurities into the polycrystalline germanium. The polycrystalline germanium is recrystallized to increase the crystal sizes in the germanium layer to not less than 5 micros to serve as a base layer on which a thin layer of gallium arsenide is vapor epitaxially grown to a selected thickness. A thermally-grown oxide layer of a thickness of several tens of angstroms is formed on the gallium arsenide layer. A metal layer, of not more about 100 angstroms thick, is deposited on the oxide layer, and a grid electrode is deposited to be in electrical contact with the top surface of the metal layer. An antireflection coating may be deposited on the exposed top surface of the metal layer.

Comparative Study of Solution Phase and Vapor Phase Deposition of Aminosilanes on Silicon Dioxide Surfaces

PubMed Central

Yadav, Amrita R.; Sriram, Rashmi; Carter, Jared A.; Miller, Benjamin L.

2014-01-01

The uniformity of aminosilane layers typically used for the modification of hydroxyl bearing surfaces such as silicon dioxide is critical for a wide variety of applications, including biosensors. However, in spite of many studies that have been undertaken on surface silanization, there remains a paucity of easy-to-implement deposition methods reproducibly yielding smooth aminosilane monolayers. In this study, solution- and vapor-phase deposition methods for three aminoalkoxysilanes differing in the number of reactive groups (3-aminopropyl triethoxysilane (APTES), 3-aminopropyl methyl diethoxysilane (APMDES) and 3-aminopropyl dimethyl ethoxysilane (APDMES)) were assessed with the aim of identifying methods that yield highly uniform and reproducible silane layers that are resistant to minor procedural variations. Silane film quality was characterized based on measured thickness, hydrophilicity and surface roughness. Additionally, hydrolytic stability of the films was assessed via these thickness and contact angle values following desorption in water. We found that two simple solution-phase methods, an aqueous deposition of APTES and a toluene based deposition of APDMES, yielded high quality silane layers that exhibit comparable characteristics to those deposited via vapor-phase methods. PMID:24411379

Method of Manufacturing a Micromechanical Oscillating Mass Balance

NASA Technical Reports Server (NTRS)

Altemir, David A. (Inventor)

1999-01-01

A micromechanical oscillating mass balance and method adapted for measuring minute quantities of material deposited at a selected location, such as during a vapor deposition process. The invention comprises a vibratory composite beam which includes a dielectric layer sandwiched between two conductive layers.The beam is positioned in a magnetic field. An alternating current passes through one conductive layers, the beam oscillates, inducing an output current in the second conductive layer, which is analyzed to determine the resonant frequency of the beam. As material is deposited on the beam, the mass of the beam increases and the resonant frequency of the beam shifts, and the mass added is determined.

Manufacturing method of photonic crystal

DOEpatents

Park, In Sung; Lee, Tae Ho; Ahn, Jin Ho; Biswas, Rana; Constant, Kristen P.; Ho, Kai-Ming; Lee, Jae-Hwang

2013-01-29

A manufacturing method of a photonic crystal is provided. In the method, a high-refractive-index material is conformally deposited on an exposed portion of a periodic template composed of a low-refractive-index material by an atomic layer deposition process so that a difference in refractive indices or dielectric constants between the template and adjacent air becomes greater, which makes it possible to form a three-dimensional photonic crystal having a superior photonic bandgap. Herein, the three-dimensional structure may be prepared by a layer-by-layer method.

Method of forming ultra thin film devices by vacuum arc vapor deposition

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor)

2005-01-01

A method for providing an ultra thin electrical circuit integral with a portion of a surface of an object, including using a focal Vacuum Arc Vapor Deposition device having a chamber, a nozzle and a nozzle seal, depressing the nozzle seal against the portion of the object surface to create an airtight compartment in the chamber and depositing one or more ultra thin film layer(s) only on the portion of the surface of the object, the layers being of distinct patterns such that they form the circuit.

In situ optical diagnostic for monitoring or control of sodium diffusion in photovoltaics manufacturing

DOEpatents

Li, Jian; Levi, Dean; Contreras, Miguel; Glynn, Stephen

2015-09-15

A method of fabricating a photovoltaic device 100, includes the steps of providing a glass substrate 102, depositing a molybdenum layer 104 on a surface of the glass substrate, directing light through the glass substrate to the near-substrate region of the molybdenum layer 206, detecting an optical property of the near-substrate region of the molybdenum layer after interaction with the incident light 208 and determining a density of the near-substrate region of the molybdenum layer from the detected optical property 210. A molybdenum deposition parameter may be controlled based upon the determined density of the near-substrate region of the molybdenum layer 218. A non-contact method measures a density of the near-substrate region of a molybdenum layer and a deposition chamber 300.

Chemically Deposited Thin-Film Solar Cell Materials

NASA Technical Reports Server (NTRS)

Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

2005-01-01

We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

Atomic Layer Deposition of Chemical Passivation Layers and High Performance Anti-Reflection Coatings on Back-Illuminated Detectors

NASA Technical Reports Server (NTRS)

Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Nikzad, Shouleh (Inventor)

2014-01-01

A back-illuminated silicon photodetector has a layer of Al2O3 deposited on a silicon oxide surface that receives electromagnetic radiation to be detected. The Al2O3 layer has an antireflection coating deposited thereon. The Al2O3 layer provides a chemically resistant separation layer between the silicon oxide surface and the antireflection coating. The Al2O3 layer is thin enough that it is optically innocuous. Under deep ultraviolet radiation, the silicon oxide layer and the antireflection coating do not interact chemically. In one embodiment, the silicon photodetector has a delta-doped layer near (within a few nanometers of) the silicon oxide surface. The Al2O3 layer is expected to provide similar protection for doped layers fabricated using other methods, such as MBE, ion implantation and CVD deposition.

Superconducting structure with layers of niobium nitride and aluminum nitride

DOEpatents

Murduck, James M.; Lepetre, Yves J.; Schuller, Ivan K.; Ketterson, John B.

1989-01-01

A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources.

Superconducting structure with layers of niobium nitride and aluminum nitride

DOEpatents

Murduck, J.M.; Lepetre, Y.J.; Schuller, I.K.; Ketterson, J.B.

1989-07-04

A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources. 8 figs.

Room temperature impact deposition of ceramic by laser shock wave

NASA Astrophysics Data System (ADS)

Jinno, Kengo; Tsumori, Fujio

2018-06-01

In this paper, a direct fine patterning of ceramics at room temperature combining 2 kinds of laser microfabrication methods is proposed. The first method is called laser-induced forward transfer and the other is called laser shock imprinting. In the proposed method, a powder material is deposited by a laser shock wave; therefore, the process is applicable to a low-melting-point material, such as a polymer substrate. In the process, a carbon layer plays an important role in the ablation by laser irradiation to generate a shock wave. This shock wave gives high shock energy to the ceramic particles, and the particles would be deposited and solidified by high-speed collision with the substrate. In this study, we performed deposition experiments by changing the thickness of the carbon layer, laser energy, thickness of the alumina layer, and gap substrates. We compared the ceramic deposits after each experiment.

Characterization of Ultrathin Ta-oxide Films Formed on Ge(100) by ALD and Layer-by-Layer Methods

NASA Astrophysics Data System (ADS)

Mishima, K.; Murakami, H.; Ohta, A.; Sahari, S. K.; Fujioka, T.; Higashi, S.; Miyazaki, S.

2013-03-01

Atomic layer deposition (ALD) and Layer-by-Layer deposition of Ta-oxide films on Ge(100) with using tris (tert-butoxy) (tert-butylimido) tantalum have been studied systematically. From the analysis of the chemical bonding features of the interface between TaOx and Ge(100) using x-ray photoelectron spectroscopy (XPS), Ge atom diffusion into the Ta oxide layer and resultant TaGexOy formation during deposition at temperatures higher than 200°C were confirmed. Also, we have demonstrated that nanometer-thick deposition of Tantalum oxide as an interfacial layer effectively suppresses the formation of GeOx in the HfO2 ALD on Ge. By the combination of TaOx pre-deposition on Ge(100) and subsequent ALD of HfO2, a capacitance equivalent thickness (CET) of 1.35 nm and relative dielectric constant of 23 were achieved.

Reactive polymer fused deposition manufacturing

DOEpatents

Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

2017-05-16

Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

Underpotential deposition-mediated layer-by-layer growth of thin films

DOEpatents

Wang, Jia Xu; Adzic, Radoslav R.

2017-06-27

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves electrochemically exchanging a mediating element on a substrate with a noble metal film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis.

Method of fabricating conductive electrodes on the front and backside of a thin film structure

DOEpatents

Tabada, Phillipe J [Roseville, CA; Tabada, legal representative, Melody; Pannu, Satinderpall S [Pleasanton, CA

2011-05-22

A method of fabricating a thin film device having conductive front and backside electrodes or contacts. Top-side cavities are first formed on a first dielectric layer, followed by the deposition of a metal layer on the first dielectric layer to fill the cavities. Defined metal structures are etched from the metal layer to include the cavity-filled metal, followed by depositing a second dielectric layer over the metal structures. Additional levels of defined metal structures may be formed in a similar manner with vias connecting metal structures between levels. After a final dielectric layer is deposited, a top surface of a metal structure of an uppermost metal layer is exposed through the final dielectric layer to form a front-side electrode, and a bottom surface of a cavity-filled portion of a metal structure of a lowermost metal layer is also exposed through the first dielectric layer to form a back-side electrode.

Conductive and robust nitride buffer layers on biaxially textured substrates

DOEpatents

Sankar, Sambasivan; Goyal, Amit; Barnett, Scott A.; Kim, Ilwon; Kroeger, Donald M.

2004-08-31

The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metal and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layers. In some embodiments the article further comprises electromagnetic devices which may be super conducting properties.

Multilayer moisture barrier

DOEpatents

Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

2015-04-21

A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

Sol-gel deposition of buffer layers on biaxially textured metal substances

DOEpatents

Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

2000-01-01

A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

Intrinsically water-repellent copper oxide surfaces; An electro-crystallization approach

NASA Astrophysics Data System (ADS)

Akbari, Raziyeh; Ramos Chagas, Gabriela; Godeau, Guilhem; Mohammadizadeh, Mohammadreza; Guittard, Frédéric; Darmanin, Thierry

2018-06-01

Use of metal oxide thin layers is increased due to their good durability under environmental conditions. In this work, the repeatable nanostructured crystalite Cu2O thin films, developed by electrodeposition method without any physical and chemical modifications, demonstrate good hydrophobicity. Copper (I) oxide (Cu2O) layers were fabricated on gold/Si(1 0 0) substrates by different electrodeposition methods i.e. galvanostatic deposition, cyclic voltammetry, and pulse potentiostatic deposition and using copper sulfate (in various concentrations) as a precursor. The greatest crystalline face on prepared Cu2O samples is (1 1 1) which is the most hydrophobic facet of Cu2O cubic structure. Indeed, different crystallite structures such as nanotriangles and truncated octahedrons were formed on the surface for various electrodeposition methods. The increase of the contact angle (θw) measured by the rest time, reaching to about 135°, was seen at different rates and electrodeposition methods. In addition, two-step deposition surfaces were also prepared by applying two of the mentioned methods, alternatively. In general, the morphology of the two-step deposition surfaces showed some changes compared to that of one-step samples, allowing the formation of different crystallite shapes. Moreover, the wettability behavior showd the larger θw of the two-step deposition layers compared to the related one-step deposition layers. Therefore, the highest observed θw was related to the one of two-step deposition layers due to the creation of small octahedral structures on the surface, having narrow and deep valleys. However, there was an exception which was due to the resulted big structures and broad valleys on the surface. So, it is possible to engineer different crystallites shapes using the proposed two-step deposition method. It is expected that hydrophobic crystallite thin films can be used in environmental and electronic applications to save energy and materials properties.

Phospho-silicate and silicate layers modified by hydroxyapatite particles

NASA Astrophysics Data System (ADS)

Rokita, M.; Brożek, A.; Handke, M.

2005-06-01

Common used metal materials do not ensure good connection between an implant and biological neighbourhood. Covering implants by thin silicate or phosphate layers enable to improve biological properties of implants and create conditions for producing the non-concrete bonding between the implant and tissue. The project includes preparing silicate sols of different concentrations and proper (powder) fraction of synthetic as well as natural ox hydroxyapatite, depositing the sol mixed with hydroxyapatite onto the base material (metal, ceramic carbon) and heat treatment. Our work includes also preparation of phospho-silicate layers deposited onto different base materials using sol-gel method. Deposited sols were prepared regarding composition, concentration and layer heat treatment conditions. The prepared layers are examined to determine their phase composition (XRD, IR spectroscopy methods), density and continuity (scanning microscopy with EDX methods). Biological activity of layers was evaluated by means of estimation of their corrosive resistance in synthetic body fluids ('in vitro' method) and of bone cells growth on the layers surface. Introducing hydroxyapatite to the layer sol should improve connection between tissue and implant as well as limit the disadvantageous, corrosive influence of implant material (metal) on the tissue.

Method for bonding thin film thermocouples to ceramics

DOEpatents

Kreider, Kenneth G.

1993-01-01

A method is provided for adhering a thin film metal thermocouple to a ceramic substrate used in an environment up to 700 degrees Centigrade, such as at a cylinder of an internal combustion engine. The method includes the steps of: depositing a thin layer of a reactive metal on a clean ceramic substrate; and depositing thin layers of platinum and a platinum-10% rhodium alloy forming the respective legs of the thermocouple on the reactive metal layer. The reactive metal layer serves as a bond coat between the thin noble metal thermocouple layers and the ceramic substrate. The thin layers of noble metal are in the range of 1-4 micrometers thick. Preferably, the ceramic substrate is selected from the group consisting of alumina and partially stabilized zirconia. Preferably, the thin layer of reactive metal is in the range of 0.015-0.030 micrometers (15-30 nanometers) thick. The preferred reactive metal is chromium. Other reactive metals may be titanium or zirconium. The thin layer of reactive metal may be deposited by sputtering in ultra high purity argon in a vacuum of approximately 2 milliTorr (0.3 Pascals).

All-vapor processing of p-type tellurium-containing II-VI semiconductor and ohmic contacts thereof

DOEpatents

McCandless, Brian E.

2001-06-26

An all dry method for producing solar cells is provided comprising first heat-annealing a II-VI semiconductor; enhancing the conductivity and grain size of the annealed layer; modifying the surface and depositing a tellurium layer onto the enhanced layer; and then depositing copper onto the tellurium layer so as to produce a copper tellurium compound on the layer.

Comparative study of solution-phase and vapor-phase deposition of aminosilanes on silicon dioxide surfaces.

PubMed

Yadav, Amrita R; Sriram, Rashmi; Carter, Jared A; Miller, Benjamin L

2014-02-01

The uniformity of aminosilane layers typically used for the modification of hydroxyl bearing surfaces such as silicon dioxide is critical for a wide variety of applications, including biosensors. However, in spite of many studies that have been undertaken on surface silanization, there remains a paucity of easy-to-implement deposition methods reproducibly yielding smooth aminosilane monolayers. In this study, solution- and vapor-phase deposition methods for three aminoalkoxysilanes differing in the number of reactive groups (3-aminopropyl triethoxysilane (APTES), 3-aminopropyl methyl diethoxysilane (APMDES) and 3-aminopropyl dimethyl ethoxysilane (APDMES)) were assessed with the aim of identifying methods that yield highly uniform and reproducible silane layers that are resistant to minor procedural variations. Silane film quality was characterized based on measured thickness, hydrophilicity and surface roughness. Additionally, hydrolytic stability of the films was assessed via these thickness and contact angle values following desorption in water. We found that two simple solution-phase methods, an aqueous deposition of APTES and a toluene based deposition of APDMES, yielded high quality silane layers that exhibit comparable characteristics to those deposited via vapor-phase methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Thick adherent dielectric films on plastic substrates and method for depositing same

DOEpatents

Wickboldt, Paul; Ellingboe, Albert R.; Theiss, Steven D.; Smith, Patrick M.

2002-01-01

Thick adherent dielectric films deposited on plastic substrates for use as a thermal barrier layer to protect the plastic substrates from high temperatures which, for example, occur during laser annealing of layers subsequently deposited on the dielectric films. It is desirable that the barrier layer has properties including: a thickness of 1 .mu.m or greater, adheres to a plastic substrate, does not lift-off when cycled in temperature, has few or no cracks and does not crack when subjected to bending, resistant to lift-off when submersed in fluids, electrically insulating and preferably transparent. The thick barrier layer may be composed, for example, of a variety of dielectrics and certain metal oxides, and may be deposited on a variety of plastic substrates by various known deposition techniques. The key to the method of forming the thick barrier layer on the plastic substrate is maintaining the substrate cool during deposition of the barrier layer. Cooling of the substrate maybe accomplished by the use of a cooling chuck on which the plastic substrate is positioned, and by directing cooling gas, such as He, Ar and N.sub.2, between the plastic substrate and the cooling chucks. Thick adherent dielectric films up to about 5 .mu.m have been deposited on plastic substrates which include the above-referenced properties, and which enable the plastic substrates to withstand laser processing temperatures applied to materials deposited on the dielectric films.

Oriented conductive oxide electrodes on SiO2/Si and glass

DOEpatents

Jia, Quanxi; Arendt, Paul N.

2001-01-01

A thin film structure is provided including a silicon substrate with a layer of silicon dioxide on a surface thereof, and a layer of cubic oxide material deposited upon the layer of silicon dioxide by ion-beam-assisted-deposition, said layer of cubic oxide material characterized as biaxially oriented. Preferably, the cubic oxide material is yttria-stabilized zirconia. Additional thin layers of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide are deposited upon the layer of yttria-stabilized zirconia. An intermediate layer of cerium oxide is employed between the yttria-stabilized zirconia layer and the lanthanum strontium cobalt oxide layer. Also, a layer of barium strontium titanium oxide can be upon the layer of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide. Also, a method of forming such thin film structures, including a low temperature deposition of a layer of a biaxially oriented cubic oxide material upon the silicon dioxide surface of a silicon dioxide/silicon substrate is provided.

Method and apparatus for detecting an analyte

DOEpatents

Allendorf, Mark D [Pleasanton, CA; Hesketh, Peter J [Atlanta, GA

2011-11-29

We describe the use of coordination polymers (CP) as coatings on microcantilevers for the detection of chemical analytes. CP exhibit changes in unit cell parameters upon adsorption of analytes, which will induce a stress in a static microcantilever upon which a CP layer is deposited. We also describe fabrication methods for depositing CP layers on surfaces.

Carbon decorative coatings by dip-, spin-, and spray-assisted layer-by-layer assembly deposition.

PubMed

Hong, Jinkee; Kang, Sang Wook

2011-09-01

We performed a comparative surface analysis of all-carbon nano-objects (multiwall carbon nanotubes (MWNT) or graphene oxide (GO) sheets) based multilayer coatings prepared using three widely used nanofilm fabrication methods: dip-, spin-, and spray-assisted layer-by-layer (LbL) deposition. The resultant films showed a marked difference in their growth mechanisms and surface morphologies. Various carbon decorative coatings were synthesized with different surface roughness values, despite identical preparation conditions. In particular, smooth to highly rough all-carbon surfaces, as determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM), were readily obtained by manipulating the LbL deposition methods. As was confirmed by the AFM and SEM analyses, this finding indicated the fundamental morphological evolution of one-dimensional nano-objects (MWNT) and two-dimensional nano-objects (GO) by control of the surface roughness through the deposition method. Therefore, an analysis of the three LbL-assembly methods presented herein may offer useful information about the industrial use of carbon decorative coatings and provide an insight into ways to control the structures of multilayer coatings by tuning the morphologies of carbon nano-objects.

System and Method for Fabricating Super Conducting Circuitry on Both Sides of an Ultra-Thin Layer

NASA Technical Reports Server (NTRS)

Brown, Ari D. (Inventor); Mikula, Vilem (Inventor)

2017-01-01

A method of fabricating circuitry in a wafer includes depositing a superconducting metal on a silicon on insulator wafer having a handle wafer, coating the wafer with a sacrificial layer and bonding the wafer to a thermally oxide silicon wafer with a first epoxy. The method includes flipping the wafer, thinning the flipped wafer by removing a handle wafer, etching a buried oxide layer, depositing a superconducting layer, bonding the wafer to a thermally oxidized silicon wafer having a handle wafer using an epoxy, flipping the wafer again, thinning the flipped wafer, etching a buried oxide layer from the wafer and etching the sacrificial layer from the wafer. The result is a wafer having superconductive circuitry on both sides of an ultra-thin silicon layer.

Method and Pd/V2 O5 device for H2 detection

DOEpatents

Liu, Ping [San Diego, CA; Tracy, C Edwin [Golden, CO; Pitts, J Roland [Lakewood, CO; Smith, II, R. Davis; Lee, Se-Hee [Lakewood, CO

2011-12-27

Methods and Pd/V.sub.2O.sub.5 devices for hydrogen detection are disclosed. An exemplary method of preparing an improved sensor for chemochromic detection of hydrogen gas over a wide response range exhibits stability during repeated coloring/bleaching cycles upon exposure and removal of hydrogen gas. The method may include providing a substrate. The method may also include depositing a V.sub.20.sub.5 layer that functions as a H.sub.2 insertion host in a Pd/V.sub.20.sub.5 hydrogen sensor to be formed on said substrate. The method may also include depositing a Pd layer onto said V.sub.20.sub.5 layer; said Pd layer functioning as an optical modulator.

Impacts of Thermal Atomic Layer-Deposited AlN Passivation Layer on GaN-on-Si High Electron Mobility Transistors.

PubMed

Zhao, Sheng-Xun; Liu, Xiao-Yong; Zhang, Lin-Qing; Huang, Hong-Fan; Shi, Jin-Shan; Wang, Peng-Fei

2016-12-01

Thermal atomic layer deposition (ALD)-grown AlN passivation layer is applied on AlGaN/GaN-on-Si HEMT, and the impacts on drive current and leakage current are investigated. The thermal ALD-grown 30-nm amorphous AlN results in a suppressed off-state leakage; however, its drive current is unchanged. It was also observed by nano-beam diffraction method that thermal ALD-amorphous AlN layer barely enhanced the polarization. On the other hand, the plasma-enhanced chemical vapor deposition (PECVD)-deposited SiN layer enhanced the polarization and resulted in an improved drive current. The capacitance-voltage (C-V) measurement also indicates that thermal ALD passivation results in a better interface quality compared with the SiN passivation.

Pulsed laser deposition of functionalized Mg-Al layered double hydroxide thin films

NASA Astrophysics Data System (ADS)

Vlad, A.; Birjega, R.; Tirca, I.; Matei, A.; Mardare, C. C.; Hassel, A. W.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.

2018-02-01

In this paper, magnesium-aluminium layered double hydroxide (LDH) has been functionalized with sodium dodecyl sulfate (DS) and deposited as thin film by pulsed laser deposition (PLD). Mg, Al-LDH powders were prepared by co-precipitation and used as reference material. Intercalation of DS as an anionic surfactant into the LDHs host layers has been prepared in two ways: co-precipitation (P) and reconstruction (R). DS intercalation occurred in LDH powder via both preparation methods. The films deposited via PLD, in particular at 532 and 1064 nm, preserve the organic intercalated layered structure of the targets prepared from these powders. The results reveal the ability of proposed deposition technique to produce functional composite organo-modified LDHs thin films.

Structural properties 3,16-bis triisopropylsilylethynyl (pentacene) (TIPS-pentacene) thin films onto organic dielectric layer using slide coating method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rusnan, Fara Naila; Mohamad, Khairul Anuar; Seria, Dzul Fahmi Mohd Husin

3,16-bis triisopropylsilylethynyl (Pentacene) (TIPS-Pentacene) compactable interface property is important in order to have a good arrangement of molecular structure. Comparison for TIPS-Pentacene deposited between two different surface layers conducted. 0.1wt% TIPS-Pentacene diluted in chloroform were deposited onto poly(methylmeaclyrate) (PMMA) layered transparent substrates using slide coating method. X-ray diffraction (XRD) used to determine crystallinity of thin films. Series of (00l) diffraction peaks obtained with sharp first peaks (001) for TIPS-Pentacene deposited onto PMMA layer at 5.35° and separation of 16.3 Å. Morphology and surface roughness were carried out using scanning electron microscope (SEM) and surface profilemeter LS500, respectively.TIPS-Pentacene deposited onto PMMAmore » layer formed needled-like-shape grains with 10.26 nm surface roughness. These properties were related as thin film formed and its surface roughness plays important role towards good mobility devices.« less

Controlled growth of larger heterojunction interface area for organic photosensitive devices

DOEpatents

Yang, Fan [Somerset, NJ; Forrest, Stephen R [Ann Arbor, MI

2009-12-29

An optoelectronic device and a method of fabricating a photosensitive optoelectronic device includes depositing a first organic semiconductor material on a first electrode to form a continuous first layer having protrusions, a side of the first layer opposite the first electrode having a surface area at least three times greater than an underlying lateral cross-sectional area; depositing a second organic semiconductor material directly on the first layer to form a discontinuous second layer, portions of the first layer remaining exposed; depositing a third organic semiconductor material directly on the second layer to form a discontinuous third layer, portions of at least the second layer remaining exposed; depositing a fourth organic semiconductor material on the third layer to form a continuous fourth layer, filling any exposed gaps and recesses in the first, second, and third layers; and depositing a second electrode on the fourth layer, wherein at least one of the first electrode and the second electrode is transparent, and the first and third organic semiconductor materials are both of a donor-type or an acceptor-type relative to second and fourth organic semiconductor materials, which are of the other material type.

Method and system for continuous atomic layer deposition

DOEpatents

Elam, Jeffrey W.; Yanguas-Gil, Angel; Libera, Joseph A.

2017-03-21

A system and method for continuous atomic layer deposition. The system and method includes a housing, a moving bed which passes through the housing, a plurality of precursor gases and associated input ports and the amount of precursor gases, position of the input ports, and relative velocity of the moving bed and carrier gases enabling exhaustion of the precursor gases at available reaction sites.

Methods of three-dimensional electrophoretic deposition for ceramic and cermet applications and systems thereof

DOEpatents

Rose, Klint Aaron; Kuntz, Joshua D.; Worsley, Marcus

2016-09-27

A ceramic, metal, or cermet according to one embodiment includes a first layer having a gradient in composition, microstructure and/or density in an x-y plane oriented parallel to a plane of deposition of the first layer. A ceramic according to another embodiment includes a plurality of layers comprising particles of a non-cubic material, wherein each layer is characterized by the particles of the non-cubic material being aligned in a common direction. Additional products and methods are also disclosed.

Systems having optical absorption layer for mid and long wave infrared and methods for making the same

DOEpatents

Kuzmenko, Paul J

2013-10-01

An optical system according to one embodiment includes a substrate; and an optical absorption layer coupled to the substrate, wherein the optical absorption layer comprises a layer of diamond-like carbon, wherein the optical absorption layer absorbs at least 50% of mid wave infrared light (3-5 .mu.m wavelength) and at least 50% of long wave infrared light (8-13 .mu.m wavelength). A method for applying an optical absorption layer to an optical system according to another embodiment includes depositing a layer of diamond-like carbon of an optical absorption layer above a substrate using plasma enhanced chemical vapor deposition, wherein the optical absorption layer absorbs at least 50% of mid wave infrared light (3-5 .mu.m wavelength) and at least 50% of long wave infrared light (8-13 .mu.m wavelength). Additional systems and methods are also presented.

Fabrication of contacts for silicon solar cells including printing burn through layers

DOEpatents

Ginley, David S; Kaydanova, Tatiana; Miedaner, Alexander; Curtis, Calvin J; Van Hest, Marinus Franciscus Antonius Maria

2014-06-24

A method for fabricating a contact (240) for a solar cell (200). The method includes providing a solar cell substrate (210) with a surface that is covered or includes an antireflective coating (220). For example, the substrate (210) may be positioned adjacent or proximate to an outlet of an inkjet printer (712) or other deposition device. The method continues with forming a burn through layer (230) on the coating (220) by depositing a metal oxide precursor (e.g., using an inkjet or other non-contact printing method to print or apply a volume of liquid or solution containing the precursor). The method includes forming a contact layer (240) comprising silver over or on the burn through layer (230), and then annealing is performed to electrically connect the contact layer (240) to the surface of the solar cell substrate (210) through a portion of the burn through layer (230) and the coating (220).

Chemical solution deposition method of fabricating highly aligned MgO templates

DOEpatents

Paranthaman, Mariappan Parans [Knoxville, TN; Sathyamurthy, Srivatsan [Knoxville, TN; Aytug, Tolga [Knoxville, TN; Arendt, Paul N [Los Alamos, NM; Stan, Liliana [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM

2012-01-03

A superconducting article includes a substrate having an untextured metal surface; an untextured barrier layer of La.sub.2Zr.sub.2O.sub.7 or Gd.sub.2Zr.sub.2O.sub.7 supported by and in contact with the surface of the substrate; a biaxially textured buffer layer supported by the untextured barrier layer; and a biaxially textured superconducting layer supported by the biaxially textured buffer layer. Moreover, a method of forming a buffer layer on a metal substrate includes the steps of: providing a substrate having an untextured metal surface; coating the surface of the substrate with a barrier layer precursor; converting the precursor to an untextured barrier layer; and depositing a biaxially textured buffer layer above and supported by the untextured barrier layer.

ZnO/CdS bi-layer nanostructures photoelectrode for dye-sensitized solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalal, Paresh V., E-mail: paresh10dalal@gmail.com; Deshpande, Milind P., E-mail: vishwadeshpande@yahoo.co.in; Solanki, Bharat G., E-mail: bhrt.solanki17@gmail.com

2016-05-06

Simple chemical deposition method for the synthesis of ZnO/CdS bilayer photoelectrode on fluorine doped tin oxide (FTO) coated glass substrate in aqueous medium at low temperature (< 373K) is described. The different preparative parameters such as deposition time, bath temperature, concentration of precursor solution and, pH of the bath etc. were optimized. Nanograined ZnO was deposited on FTO coated glass substrates by dip-coating method, whereas CdS nanorods were successfully synthesized on pre-deposited ZnO film by Chemical Bath Deposition (CBD) method. The Photovoltaic properties of FTO/ZnO/CdS bilayer photo electrodes were also studied. A maximum short circuit current density of 9.1 mA cm-2more » and conversion efficiency 1.05% are observed for ZnO/CdS-10min. Layer, which supports fast electron injection kinetics due to hetero structured nanorod, while minimum values of 0.53mA cm-2 and 0.01% respectively are observed for only ZnO deposited layer.« less

CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paranthaman, Mariappan Parans

We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCOmore » wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.« less

The electrophoretic deposition of ZnO on highly oriented pyrolytic graphite

NASA Astrophysics Data System (ADS)

Ghalamboran, Milad; Jahangiri, Mojtaba; Yousefiazari, Ehsan

2017-12-01

Intensive research has been conducted on ZnO thin and thick films in recent years. Such layers, used in different electronic devices, are deposited utilizing various methods, but electrophoretic deposition (EPD) has been chosen because of the advantages like low energy consumption, economical superiority, ecofriendliness, controllability, and high deposition rate. Here, we report electrophoretically depositing ZnO layers onto highly oriented pyrolytic graphite. Well-dispersed and stable ZnO suspensions are used for the deposition of continuous and even layers of ZnO on the substrate. ZnO powder is dispersed in acetone. The electric field applied is in the 250 V/cm to 2000 V/cm range. The morphology of the deposits are studied by SEM at the different stages of the deposition process.

Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

PubMed

Kwon, Young-Nam; Kim, In-Chul

2013-11-01

Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

Characterisation of thin films of graphene–surfactant composites produced through a novel semi-automated method

PubMed Central

Nabok, Alexei; Davis, Frank; Higson, Séamus P J

2016-01-01

Summary In this paper we detail a novel semi-automated method for the production of graphene by sonochemical exfoliation of graphite in the presence of ionic surfactants, e.g., sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). The formation of individual graphene flakes was confirmed by Raman spectroscopy, while the interaction of graphene with surfactants was proven by NMR spectroscopy. The resulting graphene–surfactant composite material formed a stable suspension in water and some organic solvents, such as chloroform. Graphene thin films were then produced using Langmuir–Blodgett (LB) or electrostatic layer-by-layer (LbL) deposition techniques. The composition and morphology of the films produced was studied with SEM/EDX and AFM. The best results in terms of adhesion and surface coverage were achieved using LbL deposition of graphene(−)SDS alternated with polyethyleneimine (PEI). The optical study of graphene thin films deposited on different substrates was carried out using UV–vis absorption spectroscopy and spectroscopic ellipsometry. A particular focus was on studying graphene layers deposited on gold-coated glass using a method of total internal reflection ellipsometry (TIRE) which revealed the enhancement of the surface plasmon resonance in thin gold films by depositing graphene layers. PMID:26977378

Method of depositing a protective layer over a biaxially textured alloy substrate and composition therefrom

DOEpatents

Goyal, Amit; Kroeger, Donald M.; Paranthaman, Mariappan; Lee, Dominic F.; Feenstra, Roeland; Norton, David P.

2002-01-01

A laminate article consists of a substrate and a biaxially textured protective layer over the substrate. The substrate can be biaxially textured and also have reduced magnetism over the magnetism of Ni. The substrate can be selected from the group consisting of nickel, copper, iron, aluminum, silver and alloys containing any of the foregoing. The protective layer can be selected from the group consisting of gold, silver, platinum, palladium, and nickel and alloys containing any of the foregoing. The protective layer is also non-oxidizable under conditions employed to deposit a desired, subsequent oxide buffer layer. Layers of YBCO, CeO.sub.2, YSZ, LaAlO.sub.3, SrTiO.sub.3, Y.sub.2 O.sub.3, RE.sub.2 O.sub.3, SrRuO.sub.3, LaNiO.sub.3 and La.sub.2 ZrO.sub.3 can be deposited over the protective layer. A method of forming the laminate article is also disclosed.

Method of transferring strained semiconductor structure

DOEpatents

Nastasi, Michael A [Santa Fe, NM; Shao, Lin [College Station, TX

2009-12-29

The transfer of strained semiconductor layers from one substrate to another substrate involves depositing a multilayer structure on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the deposited multilayer structure is bonded to a second substrate and is separated away at the interface, which results in transferring a multilayer structure from one substrate to the other substrate. The multilayer structure includes at least one strained semiconductor layer and at least one strain-induced seed layer. The strain-induced seed layer can be optionally etched away after the layer transfer.

Effects of surface passivation dielectrics on carrier transport in AlGaN/GaN heterostructure field-effect transistors

NASA Astrophysics Data System (ADS)

Oh, Sejoon; Jang, Han-Soo; Choi, Chel-Jong; Cho, Jaehee

2018-04-01

Dielectric layers prepared by different deposition methods were used for the surface passivation of AlGaN/GaN heterostructure field-effect transistors (HFETs) and the corresponding electrical characteristics were examined. Increases in the sheet charge density and the maximum drain current by approximately 45% and 28%, respectively, were observed after the deposition of a 100 nm-thick SiO2 layer by plasma-enhanced chemical vapor deposition (PECVD) on the top of the AlGaN/GaN HFETs. However, SiO2 deposited by a radio frequency (rf) sputter system had the opposite effect. As the strain applied to AlGaN was influenced by the deposition methods used for the dielectric layers, the carrier transport in the two-dimensional electron gas formed at the interface between AlGaN and GaN was affected accordingly.

Doping control by ALD surface functionalization

DOEpatents

Elam, Jeffrey W.; Yanguas-Gil, Angel

2015-02-10

Systems and methods for producing a material of desired thickness. Deposition techniques such as atomic layer deposition are alter to control the thickness of deposited material. A funtionalization species inhibits the deposition reaction.

An Introduction to Atomic Layer Deposition

NASA Technical Reports Server (NTRS)

Dwivedi, Vivek H.

2017-01-01

Atomic Layer Deposition has been instrumental in providing a deposition method for multiple space flight applications. It is well known that ALD is a cost effective nanoadditive-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign temperature and pressure environment. Through the introduction of paired precursor gases, thin films can be deposited on a myriad of substrates from flat surfaces to those with significant topography. By providing atomic layer control, where single layers of atoms can be deposited, the fabrication of metal transparent films, precise nano-laminates, and coatings of nano-channels, pores and particles is achievable. The feasibility of this technology for NASA line of business applications range from thermal systems, optics, sensors, to environmental protection. An overview of this technology will be presented.

Solar cells and methods of fabrication thereof

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shumate, Seth Daniel; Hutchings, Douglas Arthur; Mohammed, Hafeezuddin

A passivation layer is deposited on a first portion of a region of the solar cell. A grid line is deposited on a second portion of the region. The passivation layer is annealed to drive chemical species from the passivation layer to deactivate an electrical activity of a dopant in the first portion of the region of the solar cell.

Hybrid window layer for photovoltaic cells

DOEpatents

Deng, Xunming

2010-02-23

A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

Hybrid window layer for photovoltaic cells

DOEpatents

Deng, Xunming [Syvania, OH; Liao, Xianbo [Toledo, OH; Du, Wenhui [Toledo, OH

2011-10-04

A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

Hybrid window layer for photovoltaic cells

DOEpatents

Deng, Xunming [Sylvania, OH; Liao, Xianbo [Toledo, OH; Du, Wenhui [Toledo, OH

2011-02-01

A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

Method for depositing high-quality microcrystalline semiconductor materials

DOEpatents

Guha, Subhendu [Bloomfield Hills, MI; Yang, Chi C [Troy, MI; Yan, Baojie [Rochester Hills, MI

2011-03-08

A process for the plasma deposition of a layer of a microcrystalline semiconductor material is carried out by energizing a process gas which includes a precursor of the semiconductor material and a diluent with electromagnetic energy so as to create a plasma therefrom. The plasma deposits a layer of the microcrystalline semiconductor material onto the substrate. The concentration of the diluent in the process gas is varied as a function of the thickness of the layer of microcrystalline semiconductor material which has been deposited. Also disclosed is the use of the process for the preparation of an N-I-P type photovoltaic device.

Process for fabricating polycrystalline semiconductor thin-film solar cells, and cells produced thereby

DOEpatents

Wu, Xuanzhi; Sheldon, Peter

2000-01-01

A novel, simplified method for fabricating a thin-film semiconductor heterojunction photovoltaic device includes initial steps of depositing a layer of cadmium stannate and a layer of zinc stannate on a transparent substrate, both by radio frequency sputtering at ambient temperature, followed by the depositing of dissimilar layers of semiconductors such as cadmium sulfide and cadmium telluride, and heat treatment to convert the cadmium stannate to a substantially single-phase material of a spinel crystal structure. Preferably, the cadmium sulfide layer is also deposited by radio frequency sputtering at ambient temperature, and the cadmium telluride layer is deposited by close space sublimation at an elevated temperature effective to convert the amorphous cadmium stannate to the polycrystalline cadmium stannate with single-phase spinel structure.

Method of making maximally dispersed heterogeneous catalysts

DOEpatents

Jennison, Dwight R [Albuquerque, NM

2005-11-15

A method of making a catalyst with monolayer or sub-monolayer metal by controlling the wetting characteristics on the support surface and increasing the adhesion between the catalytic metal and an oxide layer. There are two methods that have been demonstrated by experiment and supported by theory. In the first method, which is useful for noble metals as well as others, a negatively-charged species is introduced to the surface of a support in sub-ML coverage. The layer-by-layer growth of metal deposited onto the oxide surface is promoted because the adhesion strength of the metal-oxide interface is increased. This method can also be used to achieve nanoislands of metal upon sub-ML deposition. The negatively-charged species can either be deposited onto the oxide surface or a compound can be deposited that dissociates on, or reacts with, the surface to form the negatively-charged species. The deposited metal adatoms can thereby bond laterally to the negatively-charged species as well as vertically to the oxide surface. Thus the negatively-charged species serve as anchors for the metal. In the second method, a chemical reaction that occurs when most metals are deposited on a fully hydroxylated oxide surface is used to create cationic metal species that bind strongly both to the substrate and to metallic metal atoms. These are incorporated into the top layer of the substrate and bind strongly both to the substrate and to metallic metal atoms. In this case, these oxidized metal atoms serve as the anchors. Here, as in the previous method, nanoislands of catalytic metal can be achieved to increase catalytic activity, or monolayers or bilayers of reactive metal can also be made.

In-situ vacuum deposition technique of lithium on neutron production target for BNCT

NASA Astrophysics Data System (ADS)

Ishiyama, S.; Baba, Y.; Fujii, R.; Nakamura, M.; Imahori, Y.

2012-10-01

For the purpose of avoiding the radiation blistering of the lithium target for neutron production in BNCT (Boron Neutron Capture Therapy) device, trilaminar Li target, of which palladium thin layer was inserted between cupper substrate and Li layer, was newly designed. In-situ vacuum deposition and electrolytic coating techniques were applied to validate the method of fabrication of the Li/Pd/Cu target, and the layered structures of the synthesized target were characterized. In-situ vacuum re-deposition technique was also established for repairing and maintenance for lithium target damaged. Following conclusions were derived; (1) Uniform lithium layers with the thickness from 1.6 nm to a few hundreds nanometer were formed on Pd/Cu multilayer surface by in situ vacuum deposition technique using metallic lithium as a source material. (2) Re-deposition of lithium layer on Li surface can be achieved by in situ vacuum deposition technique. (3) Small amount of water and carbonate was observed on the top surface of Li. But the thickness of the adsorbed layer was less than monolayer, which will not affect the quality of the Li target. (4) The formation of Pd-Li alloy layer was observed at the Pd and Li interface. The alloy layer would contribute to the stability of the Li layer.

Improved method of preparing p-i-n junctions in amorphous silicon semiconductors

DOEpatents

Madan, A.

1984-12-10

A method of preparing p/sup +/-i-n/sup +/ junctions for amorphous silicon semiconductors includes depositing amorphous silicon on a thin layer of trivalent material, such as aluminum, indium, or gallium at a temperature in the range of 200/sup 0/C to 250/sup 0/C. At this temperature, the layer of trivalent material diffuses into the amorphous silicon to form a graded p/sup +/-i junction. A layer of n-type doped material is then deposited onto the intrinsic amorphous silicon layer in a conventional manner to finish forming the p/sup +/-i-n/sup +/ junction.

Fast process flow, on-wafer interconnection and singulation for MEPV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okandan, Murat; Nielson, Gregory N.; Cruz-Campa, Jose Luis

2017-01-31

A method including providing a substrate comprising a device layer on which a plurality of device cells are defined; depositing a first dielectric layer on the device layer and metal interconnect such that the deposited interconnect is electrically connected to at least two of the device cells; depositing a second dielectric layer over the interconnect; and exposing at least one contact point on the interconnect through the second dielectric layer. An apparatus including a substrate having defined thereon a device layer including a plurality of device cells; a first dielectric layer disposed directly on the device layer; a plurality ofmore » metal interconnects, each of which is electrically connected to at least two of the device cells; and a second dielectric layer disposed over the first dielectric layer and over the interconnects, wherein the second dielectric layer is patterned in a positive or negative planar spring pattern.« less

Fast process flow, on-wafer interconnection and singulation for MEPV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okandan, Murat; Nielson, Gregory N.; Cruz-Campa, Jose Luis

2017-08-29

A method including providing a substrate comprising a device layer on which a plurality of device cells are defined; depositing a first dielectric layer on the device layer and metal interconnect such that the deposited interconnect is electrically connected to at least two of the device cells; depositing a second dielectric layer over the interconnect; and exposing at least one contact point on the interconnect through the second dielectric layer. An apparatus including a substrate having defined thereon a device layer including a plurality of device cells; a first dielectric layer disposed directly on the device layer; a plurality ofmore » metal interconnects, each of which is electrically connected to at least two of the device cells; and a second dielectric layer disposed over the first dielectric layer and over the interconnects, wherein the second dielectric layer is patterned in a positive or negative planar spring pattern.« less

Atomic layer deposited oxide films as protective interface layers for integrated graphene transfer

NASA Astrophysics Data System (ADS)

Cabrero-Vilatela, A.; Alexander-Webber, J. A.; Sagade, A. A.; Aria, A. I.; Braeuninger-Weimer, P.; Martin, M.-B.; Weatherup, R. S.; Hofmann, S.

2017-12-01

The transfer of chemical vapour deposited graphene from its parent growth catalyst has become a bottleneck for many of its emerging applications. The sacrificial polymer layers that are typically deposited onto graphene for mechanical support during transfer are challenging to remove completely and hence leave graphene and subsequent device interfaces contaminated. Here, we report on the use of atomic layer deposited (ALD) oxide films as protective interface and support layers during graphene transfer. The method avoids any direct contact of the graphene with polymers and through the use of thicker ALD layers (≥100 nm), polymers can be eliminated from the transfer-process altogether. The ALD film can be kept as a functional device layer, facilitating integrated device manufacturing. We demonstrate back-gated field effect devices based on single-layer graphene transferred with a protective Al2O3 film onto SiO2 that show significantly reduced charge trap and residual carrier densities. We critically discuss the advantages and challenges of processing graphene/ALD bilayer structures.

Stabilization of green bodies via sacrificial gelling agent during electrophoretic deposition

DOEpatents

Worsley, Marcus A.; Kuntz, Joshua D.; Rose, Klint A.

2016-03-22

In one embodiment, a method for electrophoretic deposition of a three-dimensionally patterned green body includes suspending a first material in a gelling agent above a patterned electrode of an electrophoretic deposition (EPD) chamber, and gelling the suspension while applying a first electric field to the suspension to cause desired patterning of the first material in a resulting gelation. In another embodiment, a ceramic, metal, or cermet includes a plurality of layers, wherein each layer includes a gradient in composition, microstructure, and/or density in an x-y plane oriented parallel to a plane of deposition of the plurality of layers along a predetermined distance in a z-direction perpendicular to the plane of deposition.

Organic photosensitive cells grown on rough electrode with nano-scale morphology control

DOEpatents

Yang, Fan [Piscataway, NJ; Forrest, Stephen R [Ann Arbor, MI

2011-06-07

An optoelectronic device and a method for fabricating the optoelectronic device includes a first electrode disposed on a substrate, an exposed surface of the first electrode having a root mean square roughness of at least 30 nm and a height variation of at least 200 nm, the first electrode being transparent. A conformal layer of a first organic semiconductor material is deposited onto the first electrode by organic vapor phase deposition, the first organic semiconductor material being a small molecule material. A layer of a second organic semiconductor material is deposited over the conformal layer. At least some of the layer of the second organic semiconductor material directly contacts the conformal layer. A second electrode is deposited over the layer of the second organic semiconductor material. The first organic semiconductor material is of a donor-type or an acceptor-type relative to the second organic semiconductor material, which is of the other material type.

Device and methods for writing and erasing analog information in small memory units via voltage pulses

DOEpatents

El Gabaly Marquez, Farid; Talin, Albert Alec

2018-04-17

Devices and methods for non-volatile analog data storage are described herein. In an exemplary embodiment, an analog memory device comprises a potential-carrier source layer, a barrier layer deposited on the source layer, and at least two storage layers deposited on the barrier layer. The memory device can be prepared to write and read data via application of a biasing voltage between the source layer and the storage layers, wherein the biasing voltage causes potential-carriers to migrate into the storage layers. After initialization, data can be written to the memory device by application of a voltage pulse between two storage layers that causes potential-carriers to migrate from one storage layer to another. A difference in concentration of potential carriers caused by migration of potential-carriers between the storage layers results in a voltage that can be measured in order to read the written data.

Method of depositing multi-layer carbon-based coatings for field emission

DOEpatents

Sullivan, John P.; Friedmann, Thomas A.

1999-01-01

A novel field emitter device for cold cathode field emission applications, comprising a multi-layer resistive carbon film. The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. Field emitters made according the present invention display improved electron emission characteristics in comparison to conventional field emitter materials.

Method of depositing multi-layer carbon-based coatings for field emission

DOEpatents

Sullivan, J.P.; Friedmann, T.A.

1999-08-10

A novel field emitter device is disclosed for cold cathode field emission applications, comprising a multi-layer resistive carbon film. The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. Field emitters made according the present invention display improved electron emission characteristics in comparison to conventional field emitter materials. 8 figs.

Oxygen-reducing catalyst layer

DOEpatents

O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

2011-03-22

An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

Error Analysis of Indirect Broadband Monitoring of Multilayer Optical Coatings using Computer Simulations

NASA Astrophysics Data System (ADS)

Semenov, Z. V.; Labusov, V. A.

2017-11-01

Results of studying the errors of indirect monitoring by means of computer simulations are reported. The monitoring method is based on measuring spectra of reflection from additional monitoring substrates in a wide spectral range. Special software (Deposition Control Simulator) is developed, which allows one to estimate the influence of the monitoring system parameters (noise of the photodetector array, operating spectral range of the spectrometer and errors of its calibration in terms of wavelengths, drift of the radiation source intensity, and errors in the refractive index of deposited materials) on the random and systematic errors of deposited layer thickness measurements. The direct and inverse problems of multilayer coatings are solved using the OptiReOpt library. Curves of the random and systematic errors of measurements of the deposited layer thickness as functions of the layer thickness are presented for various values of the system parameters. Recommendations are given on using the indirect monitoring method for the purpose of reducing the layer thickness measurement error.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals

NASA Astrophysics Data System (ADS)

Carey, Benjamin J.; Ou, Jian Zhen; Clark, Rhiannon M.; Berean, Kyle J.; Zavabeti, Ali; Chesman, Anthony S. R.; Russo, Salvy P.; Lau, Desmond W. M.; Xu, Zai-Quan; Bao, Qiaoliang; Kevehei, Omid; Gibson, Brant C.; Dickey, Michael D.; Kaner, Richard B.; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-02-01

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (~1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals.

PubMed

Carey, Benjamin J; Ou, Jian Zhen; Clark, Rhiannon M; Berean, Kyle J; Zavabeti, Ali; Chesman, Anthony S R; Russo, Salvy P; Lau, Desmond W M; Xu, Zai-Quan; Bao, Qiaoliang; Kevehei, Omid; Gibson, Brant C; Dickey, Michael D; Kaner, Richard B; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-02-17

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals

PubMed Central

Carey, Benjamin J.; Ou, Jian Zhen; Clark, Rhiannon M.; Berean, Kyle J.; Zavabeti, Ali; Chesman, Anthony S. R.; Russo, Salvy P.; Lau, Desmond W. M.; Xu, Zai-Quan; Bao, Qiaoliang; Kavehei, Omid; Gibson, Brant C.; Dickey, Michael D.; Kaner, Richard B.; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-01-01

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes. PMID:28211538

Part 2: Sedimentary geology of the Valles, Marineris, Mars and Antarctic dry valley lakes

NASA Technical Reports Server (NTRS)

Nedell, Susan S.

1987-01-01

Detailed mapping of the layered deposits in the Valles Marineris, Mars from high-resolution Viking orbiter images revealed that they from plateaus of rhythmically layered material whose bases are in the lowest elevations of the canyon floors, and whose tops are within a few hundred meters in elevation of the surrounding plateaus. Four hypotheses for the origin of the layered deposits were considered: that they are eolian deposits; that they are remnants of the same material as the canyon walls; that they are explosive volcanic deposits; or that they were deposited in standing bodies of water. There are serious morphologic objections to each of the first three. The deposition of the layered deposits in standing bodies of water best explains their lateral continuity, horizontality, great thickness, rhythmic nature, and stratigraphic relationships with other units within the canyons. The Martian climatic history indicated that any ancient lakes were ice covered. Two methods for transporting sediment through a cover of ice on a martian lake appear to be feasible. Based on the presently available data, along with the theoretical calculations presented, it appears most likely that the layered deposits in the Valles Marineris were laid down in standing bodies of water.

Effect of the Fabrication Parameters of the Nanosphere Lithography Method on the Properties of the Deposited Au-Ag Nanoparticle Arrays

PubMed Central

Liu, Jing; Chen, Chaoyang; Yang, Guangsong; Chen, Yushan; Yang, Cheng-Fu

2017-01-01

The nanosphere lithography (NSL) method can be developed to deposit the Au-Ag triangle hexagonal nanoparticle arrays for the generation of localized surface plasmon resonance. Previously, we have found that the parameters used to form the NSL masks and the physical methods required to deposit the Au-Ag thin films had large effects on the geometry properties of the nanoparticle arrays. Considering this, the different parameters used to grow the Au-Ag triangle hexagonal nanoparticle arrays were investigated. A single-layer NSL mask was formed by using self-assembly nano-scale polystyrene (PS) nanospheres with an average radius of 265 nm. At first, the concentration of the nano-scale PS nanospheres in the solution was set at 6 wt %. Two coating methods, drop-coating and spin-coating, were used to coat the nano-scale PS nanospheres as a single-layer NSL mask. From the observations of scanning electronic microscopy (SEM), we found that the matrixes of the PS nanosphere masks fabricated by using the drop-coating method were more uniform and exhibited a smaller gap than those fabricated by the spin-coating method. Next, the drop-coating method was used to form the single-layer NSL mask and the concentration of nano-scale PS nanospheres in a solution that was changed from 4 to 10 wt %, for further study. The SEM images showed that when the concentrations of PS nanospheres in the solution were 6 and 8 wt %, the matrixes of the PS nanosphere masks were more uniform than those of 4 and 10 wt %. The effects of the one-side lifting angle of substrates and the vaporization temperature for the solvent of one-layer self-assembly PS nanosphere thin films, were also investigated. Finally, the concentration of the nano-scale PS nanospheres in the solution was set at 8 wt % to form the PS nanosphere masks by the drop-coating method. Three different physical deposition methods, including thermal evaporation, radio-frequency magnetron sputtering, and e-gun deposition, were used to deposit the Au-Ag triangle hexagonal periodic nanoparticle arrays. The SEM images showed that as the single-layer PS nanosphere mask was well controlled, the thermal evaporation could deposit the Au-Ag triangle hexagonal nanoparticle arrays with a higher quality than the other two methods. PMID:28772741

Effect of the Fabrication Parameters of the Nanosphere Lithography Method on the Properties of the Deposited Au-Ag Nanoparticle Arrays.

PubMed

Liu, Jing; Chen, Chaoyang; Yang, Guangsong; Chen, Yushan; Yang, Cheng-Fu

2017-04-03

The nanosphere lithography (NSL) method can be developed to deposit the Au-Ag triangle hexagonal nanoparticle arrays for the generation of localized surface plasmon resonance. Previously, we have found that the parameters used to form the NSL masks and the physical methods required to deposit the Au-Ag thin films had large effects on the geometry properties of the nanoparticle arrays. Considering this, the different parameters used to grow the Au-Ag triangle hexagonal nanoparticle arrays were investigated. A single-layer NSL mask was formed by using self-assembly nano-scale polystyrene (PS) nanospheres with an average radius of 265 nm. At first, the concentration of the nano-scale PS nanospheres in the solution was set at 6 wt %. Two coating methods, drop-coating and spin-coating, were used to coat the nano-scale PS nanospheres as a single-layer NSL mask. From the observations of scanning electronic microscopy (SEM), we found that the matrixes of the PS nanosphere masks fabricated by using the drop-coating method were more uniform and exhibited a smaller gap than those fabricated by the spin-coating method. Next, the drop-coating method was used to form the single-layer NSL mask and the concentration of nano-scale PS nanospheres in a solution that was changed from 4 to 10 wt %, for further study. The SEM images showed that when the concentrations of PS nanospheres in the solution were 6 and 8 wt %, the matrixes of the PS nanosphere masks were more uniform than those of 4 and 10 wt %. The effects of the one-side lifting angle of substrates and the vaporization temperature for the solvent of one-layer self-assembly PS nanosphere thin films, were also investigated. Finally, the concentration of the nano-scale PS nanospheres in the solution was set at 8 wt % to form the PS nanosphere masks by the drop-coating method. Three different physical deposition methods, including thermal evaporation, radio-frequency magnetron sputtering, and e-gun deposition, were used to deposit the Au-Ag triangle hexagonal periodic nanoparticle arrays. The SEM images showed that as the single-layer PS nanosphere mask was well controlled, the thermal evaporation could deposit the Au-Ag triangle hexagonal nanoparticle arrays with a higher quality than the other two methods.

Method for fabrication of electrodes

DOEpatents

Jankowski, Alan F.; Morse, Jeffrey D.; Barksdale, Randy

2004-06-22

Described herein is a method to fabricate porous thin-film electrodes for fuel cells and fuel cell stacks. Furthermore, the method can be used for all fuel cell electrolyte materials which utilize a continuous electrolyte layer. An electrode layer is deposited on a porous host structure by flowing gas (for example, Argon) from the bottomside of the host structure while simultaneously depositing a conductive material onto the topside of the host structure. By controlling the gas flow rate through the pores, along with the process conditions and deposition rate of the thin-film electrode material, a film of a pre-determined thickness can be formed. Once the porous electrode is formed, a continuous electrolyte thin-film is deposited, followed by a second porous electrode to complete the fuel cell structure.

Metal deposition using seed layers

DOEpatents

Feng, Hsein-Ping; Chen, Gang; Bo, Yu; Ren, Zhifeng; Chen, Shuo; Poudel, Bed

2013-11-12

Methods of forming a conductive metal layers on substrates are disclosed which employ a seed layer to enhance bonding, especially to smooth, low-roughness or hydrophobic substrates. In one aspect of the invention, the seed layer can be formed by applying nanoparticles onto a surface of the substrate; and the metallization is achieved by electroplating an electrically conducting metal onto the seed layer, whereby the nanoparticles serve as nucleation sites for metal deposition. In another approach, the seed layer can be formed by a self-assembling linker material, such as a sulfur-containing silane material.

Method of deforming a biaxially textured buffer layer on a textured metallic substrate and articles therefrom

DOEpatents

Lee, Dominic F.; Kroeger, Donald M.; Goyal, Amit

2000-01-01

The present invention provides methods and biaxially textured articles having a deformed epitaxial layer formed therefrom for use with high temperature superconductors, photovoltaic, ferroelectric, or optical devices. A buffer layer is epitaxially deposited onto biaxially-textured substrates and then mechanically deformed. The deformation process minimizes or eliminates grooves, or other irregularities, formed on the buffer layer while maintaining the biaxial texture of the buffer layer. Advantageously, the biaxial texture of the buffer layer is not altered during subsequent heat treatments of the deformed buffer. The present invention provides mechanical densification procedures which can be incorporated into the processing of superconducting films through the powder deposit or precursor approaches without incurring unfavorable high-angle grain boundaries.

Influence of the Preparation Method on Planar Perovskite CH3NH3PbI3-xClx Solar Cell Performance and Hysteresis

NASA Astrophysics Data System (ADS)

Ivanova, A.; Tokmakov, A.; Lebedeva, K.; Roze, M.; Kaulachs, I.

2017-08-01

Organometal halide perovskites are promising materials for lowcost, high-efficiency solar cells. The method of perovskite layer deposition and the interfacial layers play an important role in determining the efficiency of perovskite solar cells (PSCs). In the paper, we demonstrate inverted planar perovskite solar cells where perovskite layers are deposited by two-step modified interdiffusion and one-step methods. We also demonstrate how PSC parameters change by doping of charge transport layers (CTL). We used dimethylsupoxide (DMSO) as dopant for the hole transport layer (PEDOT:PSS) but for the electron transport layer [6,6]-phenyl C61 butyric acid methyl ester (PCBM)) we used N,N-dimethyl-N-octadecyl(3-aminopropyl)trimethoxysilyl chloride (DMOAP). The highest main PSC parameters (PCE, EQE, VOC) were obtained for cells prepared by the one-step method with fast crystallization and doped CTLs but higher fill factor (FF) and shunt resistance (Rsh) values were obtained for cells prepared by the two-step method with undoped CTLs.

Method for fabricating photovoltaic device having improved short wavelength photoresponse

DOEpatents

Catalano, Anthony W.

1989-07-04

Amorphous p-i-n silicon photovoltaic cells with improved short wavelength photoresponse are fabricated with reduced p-dopant contamination at the p/i interface. Residual p-dopants are removed by flushing the deposition chamber with a gaseous mixture capable of reacting with excess doping contaminants prior to the deposition of the i-layer and subsequent to the deposition of the p-layer.

Epitaxial Deposition Of Germanium Doped With Gallium

NASA Technical Reports Server (NTRS)

Huffman, James E.

1994-01-01

Epitaxial layers of germanium doped with gallium made by chemical vapor deposition. Method involves combination of techniques and materials used in chemical vapor deposition with GeH4 or GeCl4 as source of germanium and GaCl3 as source of gallium. Resulting epitaxial layers of germanium doped with gallium expected to be highly pure, with high crystalline quality. High-quality material useful in infrared sensors.

Growth and dielectric properties of ZnO nanoparticles deposited by using electrophoretic deposition

NASA Astrophysics Data System (ADS)

Chung, Yoonsung; Park, Hyejin; Kim, Dong-Joo; Cho, Sung Baek; Yoon, Young Soo

2015-05-01

The deposition behavior of ZnO nanoparticles on metal plates and conductive fabrics was investigated using electrophoretic deposition (EPD). The deposition kinetics on both metal plates and fabrics were examined using the Hamaker equation. Fabric substrates give more deposited weight than flat substrates due to their rougher shape and higher surface area. The morphologies and the structures of the deposited ZnO layers showed uniform deposition without any preferred orientation on both substrates. The dielectric properties of the ZnO layers formed by using EPD showed values that were reduced, but comparable to those of bulk ZnO. This result suggests that EPD is a convenient method to deposit functional oxides on flexible substrates.

Apparatus and method of manufacture for depositing a composite anti-reflection layer on a silicon surface

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor)

2012-01-01

An apparatus and associated method are provided. A first silicon layer having at least one of an associated passivation layer and barrier is included. Also included is a composite anti-reflection layer including a stack of layers each with a different thickness and refractive index. Such composite anti-reflection layer is disposed adjacent to the first silicon layer.

Graphene-based stretchable and transparent moisture barrier

NASA Astrophysics Data System (ADS)

Won, Sejeong; Van Lam, Do; Lee, Jin Young; Jung, Hyun-June; Hur, Min; Kim, Kwang-Seop; Lee, Hak-Joo; Kim, Jae-Hyun

2018-03-01

We propose an alumina-deposited double-layer graphene (2LG) as a transparent, scalable, and stretchable barrier against moisture; this barrier is indispensable for foldable or stretchable organic displays and electronics. Both the barrier property and stretchability were significantly enhanced through the introduction of 2LG between alumina and a polymeric substrate. 2LG with negligible polymeric residues was coated on the polymeric substrate via a scalable dry transfer method in a roll-to-roll manner; an alumina layer was deposited on the graphene via atomic layer deposition. The effect of the graphene layer on crack generation in the alumina layer was systematically studied under external strain using an in situ micro-tensile tester, and correlations between the deformation-induced defects and water vapor transmission rate were quantitatively analyzed. The enhanced stretchability of alumina-deposited 2LG originated from the interlayer sliding between the graphene layers, which resulted in the crack density of the alumina layer being reduced under external strain.

Evaluation of Advanced Polymers for Additive Manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rios, Orlando; Carter, William G.; Kutchko, Cindy

The goal of this Manufacturing Demonstration Facility (MDF) technical collaboration project between Oak Ridge National Laboratory (ORNL) and PPG Industries, Inc. (PPG) was to evaluate the feasibility of using conventional coatings chemistry and technology to build up material layer-by-layer. The PPG-ORNL study successfully demonstrated that polymeric coatings formulations may overcome many limitations of common thermoplastics used in additive manufacturing (AM), allow lightweight nozzle design for material deposition, and increase build rate. The materials effort focused on layer-by-layer deposition of coatings with each layer fusing together. The combination of materials and deposition results in an additively manufactured build that has sufficientmore » mechanical properties to bear the load of additional layers, yet is capable of bonding across the z-layers to improve build direction strength. The formulation properties were tuned to enable a novel, high-throughput deposition method that is highly scalable, compatible with high loading of reinforcing fillers, and inherently low-cost.« less

Improvement of light extraction of LYSO scintillator by using a combination of self-assembly of nanospheres and atomic layer deposition.

PubMed

Zhu, Zhichao; Liu, Bo; Zhang, Haifeng; Ren, Weina; Cheng, Chuanwei; Wu, Shuang; Gu, Mu; Chen, Hong

2015-03-23

The self-assembled monolayer periodic array of polystyrene spheres conformally coated with TiO₂ layer using atomic layer deposition is designed to obtain a further enhancement of light extraction for LYSO scintillator. The maximum enhancement is 149% for the sample with polystyrene spheres conformally coated with TiO₂ layer, while the enhancement is only 76% for the sample with only polystyrene spheres. Such further enhancement could be contributed from the additional modes forming by TiO₂ layer due to its high refractive index, which can be approved by the simulation of electric field distribution. The experimental results are agreement with the simulated results. Furthermore, the prepared structured layer exhibits an excellent combination with the surface of scintillator, which is in favor of the practical application. Therefore, it is safely concluded that the combination of self-assembly method and atomic layer deposition is a promising approach to obtain a significant enhancement of light extraction for a large area. This method can be extended to many other luminescent materials and devices.

Method of making a layered composite electrode/electrolyte

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2005-01-25

An electrode/electrolyte structure is prepared by a plurality of methods. An unsintered (possibly bisque fired) moderately catalytic electronically-conductive or homogeneous mixed ionic electronic conductive electrode material is deposited on a layer composed of a sintered or unsintered ionically-conductive electrolyte material prior to being sintered. A layer of particulate electrode material is deposited on an unsintered ("green") layer of electrolyte material and the electrode and electrolyte layers are sintered simultaneously, sometimes referred to as "co-firing," under conditions suitable to fully densify the electrolyte while the electrode retains porosity. Or, the layer of particulate electrode material is deposited on a previously sintered layer of electrolyte, and then sintered. Subsequently, a catalytic material is added to the electrode structure by infiltration of an electrolcatalyst precursor (e.g., a metal salt such as a transition metal nitrate). This may be followed by low temperature firing to convert the precursor to catalyst. The invention allows for an electrode with high electronic conductivity and sufficient catalytic activity to achieve high power density in an ionic (electrochemical) device such as fuel cells and electrolytic gas separation systems.

Micromechanical Oscillating Mass Balance

NASA Technical Reports Server (NTRS)

Altemir, David A. (Inventor)

1997-01-01

A micromechanical oscillating mass balance and method adapted for measuring minute quantities of material deposited at a selected location, such as during a vapor deposition process. The invention comprises a vibratory composite beam which includes a dielectric layer sandwiched between two conductive layers. The beam is positioned in a magnetic field. An alternating current passes through one conductive layers, the beam oscillates, inducing an output current in the second conductive layer, which is analyzed to determine the resonant frequency of the beam. As material is deposited on the beam, the mass of the beam increases and the resonant frequency of the beam shifts, and the mass added is determined.

Simple model for estimating dry deposition velocity of ozone and its destruction in a polluted nocturnal boundary layer

NASA Astrophysics Data System (ADS)

Lin, Ching-Ho; Lai, Chin-Hsing; Wu, Yee-Lin; Chen, Ming-Jen

2010-11-01

Determining the destructions of both ozone and odd oxygen, O x, in the nocturnal boundary layer (NBL) is important to evaluate the regional ozone budget and overnight ozone accumulation. This work develops a simple method to determine the dry deposition velocity of ozone and its destruction at a polluted nocturnal boundary layer. The destruction of O x can also be determined simultaneously. The method is based on O 3 and NO 2 profiles and their surface measurements. Linkages between the dry deposition velocities of O 3 and NO 2 and between the dry deposition loss of O x and its chemical loss are constructed and used. Field measurements are made at an agricultural site to demonstrate the application of the model. The model estimated nocturnal O 3 dry deposition velocities from 0.13 to 0.19 cm s -1, very close to those previously obtained for similar land types. Additionally, dry deposition and chemical reactions account for 60 and 40% of the overall nocturnal ozone loss, respectively; ozone dry deposition accounts for 50% of the overall nocturnal loss of O x, dry deposition of NO 2 accounts for another 20%, and chemical reactions account for the remaining 30%. The proposed method enables the use of measurements made in typical ozone field studies to evaluate various nocturnal destructions of O 3 and O x in a polluted environment.

Membrane for hydrogen recovery from streams containing hydrogen sulfide

DOEpatents

Agarwal, Pradeep K.

2007-01-16

A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

Methods for improved growth of group III nitride buffer layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphologymore » of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).« less

Optimization of Al2O3/TiO2/Al 2O3 Multilayer Antireflection Coating With X-Ray Scattering Techniques

NASA Astrophysics Data System (ADS)

Li, Chao

Broadband multilayer antireflection coatings (ARCs) are keys to improving solar cell efficiencies. The goal of this dissertation is to optimize the multilayer Al2O3/TiO2/Al2O 3 ARC designed for a III-V space multi-junction solar cell with understanding influences of post-annealing and varying deposition parameters on the optical properties. Accurately measuring optical properties is important in accessing optical performances of ARCs. The multilayer Al2O3/TiO 2/Al2O3 ARC and individual Al2O 3 and TiO2 layers were characterized by a novel X-ray reflectivity (XRR) method and a combined method of grazing-incidence small angle X-ray scattering (GISAXS), atomic force microscopy (AFM), and XRR developed in this study. The novel XRR method combining an enhanced Fourier analysis with specular XRR simulation effectively determines layer thicknesses and surface and interface roughnesses and/or grading with sub-nanometer precision, and densities less than three percent uncertainty. Also, the combined method of GISAXS, AFM, and XRR characterizes the distribution of pore size with one-nanometer uncertainty. Unique to this method, the diffuse scattering from surface and interface roughnesses is estimated with surface parameters (root mean square roughness sigma, lateral correlation length ξ, and Hurst parameter h) obtained from AFM, and layer densities, surface grading and interface roughness/grading obtained from specular XRR. It is then separated from pore scattering. These X-ray scattering techniques obtained consistent results and were validated by other techniques including optical reflectance, spectroscopic ellipsometry (SE), glancing incidence X-ray diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy. The ARCs were deposited by atomic layer deposition with standard parameters at 200 °C. The as-deposited individual Al2O3 layer on Si is porous and amorphous as indicated by the combined methods of GISAXS, AFM, and XRR. Both post-annealing at 400 °C for 40 min in air and varying ALD parameters can eliminate pores, and lead to consistent increases in density and refractive index determined by the XRR method, SE, and optical reflectance measurements. After annealing, the layer remains amorphous. On the other hand, the as-deposited TiO 2 layer is non-porous and amorphous. It is densified and crystallized after annealing at 400 °C for 10 min in air. The multilayer Al2O 3/TiO2/Al2O3 ARC deposited on Si has surface and interface roughnesses and/or grading on the order of one nanometer. Annealing at 400 °C for 10 min in air induces densification and crystallization of the amorphous TiO2 layer as well as possible chemical reactions between TiO2 and Si diffusing from the substrate. On the other hand, Al2O3 layers remain amorphous after annealing. The thickness of the top Al2O3 layer decreases - likely due to interdiffusion between the top two layers and loss of hydrogen from hydroxyl groups initially present in the ALD layers. The thickness of the bottom Al2O3 layer increases, probably due to the diffusion of Si atoms into the bottom layer. In addition, the multilayer Al 2O3/TiO2/Al2O3 ARC was deposited on AlInP (30nm) / GaInP (100nm) / GaAs that includes the topmost layers of III-V multi-junction solar cells. Reflectance below 5 % is achieved within nearly the whole wavelength range of the current-limiting sub-cell. Also, internal scattering occurs in the TiO2 layer possibly associated with the initiated crystallization in the TiO2 layer while absent in the amorphous Al2O3 layers.

Methods to induce perpendicular magnetic anisotropy in full-Heusler Co2FeSi thin layers in a magnetic tunnel junction structure

NASA Astrophysics Data System (ADS)

Shinohara, Koki; Suzuki, Takahiro; Takamura, Yota; Nakagawa, Shigeki

2018-05-01

In this study, to obtain perpendicular magnetic tunnel junctions (p-MTJs) using half-metallic ferromagnets (HMFs), several methods were developed to induce perpendicular magnetic anisotropy (PMA) in full-Heusler Co2FeSi (CFS) alloy thin layers in an MTJ multilayer composed of a layered CFS/MgO/CFS structure. Oxygen exposure at 2.0 Pa for 10 min after deposition of the bottom CFS layer was effective for obtaining PMA in the CFS layer. One of the reasons for the PMA is the formation of nearly ideal CFS/MgO interfaces due to oxygen exposure before the deposition of the MgO layer. The annealing process was effective for obtaining PMA in the top CFS layer capped with a Pd layer. PMA was clearly observed in the top CFS layer of a Cr(40 nm)/Pd(50 nm)/bottom CFS(0.6 nm)/MgO(2.0 nm)/top CFS(0.6 nm)/ Pd(10 nm) multilayer, where the top CFS and Pd thin films were deposited at RT and subsequently annealed at 300°C. In addition to the continuous layer growth of the films, the crystalline orientation alignment at the top CFS/Pd interface probably attributes to the origin of PMA at the top CFS layer.

Method for making oxygen-reducing catalyst layers

DOEpatents

O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; O'Neill, David G.

2010-06-22

Methods are provided for making oxygen-reducing catalyst layers, which include simultaneous or sequential stops of physical vapor depositing an oxygen-reducing catalytic material onto a substrate, the catalytic material comprising a transition metal that is substantially free of platinum; and thermally treating the catalytic material. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

Colloidal lithography with electrochemical nickel deposition as a unique method for improved silver decorated nanocavities in SERS applications

NASA Astrophysics Data System (ADS)

Petruš, Ondrej; Oriňak, Andrej; Oriňaková, Renáta; Orságová Králová, Zuzana; Múdra, Erika; Kupková, Miriam; Kovaľ, Karol

2017-11-01

Two types of metallised nanocavities (single and hybrid) were fabricated by colloid lithography followed by electrochemical deposition of Ni and subsequently Ag layers. Introductory Ni deposition step iniciates more homogenous decoration of nanocavities with Ag nanoparticles. Silver nanocavity decoration has been so performed with lower nucleation rate and with Ag nanoparticles homogeinity increase. By this, two step Ni and Ag deposition trough polystyrene nanospheres (100, 300, 500, 700, 900 nm), the various Ag surfaces were obtained. Ni layer formation in the first step of deposition enabled more precise controlling of Ag film deposition and thus final Ag surface morphology. Prepared substrates were tested as active surfaces in SERS application. The best SERS signal enhancement was observed at 500 nm Ag nanocavities with normalised thickness Ni layer ∼0.5. Enhancement factor has been established at value 1.078 × 1010; time stability was determined within 13 weeks; charge distribution at nanocavity Ag surfaces as well as reflection spectra were calculated by FDTD method. Newly prepared nanocavity surface can be applied in SERS analysis, predominantly.

Hybrid vapor phase-solution phase growth techniques for improved CZT(S,Se) photovoltaic device performance

DOEpatents

Chang, Liang-Yi; Gershon, Talia S.; Haight, Richard A.; Lee, Yun Seog

2016-12-27

A hybrid vapor phase-solution phase CZT(S,Se) growth technique is provided. In one aspect, a method of forming a kesterite absorber material on a substrate includes the steps of: depositing a layer of a first kesterite material on the substrate using a vapor phase deposition process, wherein the first kesterite material includes Cu, Zn, Sn, and at least one of S and Se; annealing the first kesterite material to crystallize the first kesterite material; and depositing a layer of a second kesterite material on a side of the first kesterite material opposite the substrate using a solution phase deposition process, wherein the second kesterite material includes Cu, Zn, Sn, and at least one of S and Se, wherein the first kesterite material and the second kesterite material form a multi-layer stack of the absorber material on the substrate. A photovoltaic device and method of formation thereof are also provided.

Enhanced Kinetics of Electrochemical Hydrogen Uptake and Release by Palladium Powders Modified by Electrochemical Atomic Layer Deposition

DOE PAGES

Benson, David M.; Tsang, Chu F.; Sugar, Joshua Daniel; ...

2017-04-28

One method for the formation of nanofilms of materials, is Electrochemical atomic layer deposition (E-ALD), one atomic layer at a time. It uses the galvanic exchange of a less noble metal, deposited using underpotential deposition (UPD), to produce an atomic layer of a more noble element by reduction of its ions. This process is referred to as surface limited redox replacement and can be repeated in a cycle to grow thicker deposits. Previously, we performed it on nanoparticles and planar substrates. In the present report, E-ALD is applied for coating a submicron-sized powder substrate, making use of a new flowmore » cell design. E-ALD is used to coat a Pd powder substrate with different thicknesses of Rh by exchanging it for Cu UPD. Furthermore, cyclic voltammetry and X-ray photoelectron spectroscopy indicate an increasing Rh coverage with increasing numbers of deposition cycles performed, in a manner consistent with the atomic layer deposition (ALD) mechanism. Cyclic voltammetry also indicated increased kinetics of H sorption and desorption in and out of the Pd powder with Rh present, relative to unmodified Pd.« less

How Does a SILAR CdSe Film Grow? Tuning the Deposition Steps to Suppress Interfacial Charge Recombination in Solar Cells.

PubMed

Becker, Matthew A; Radich, James G; Bunker, Bruce A; Kamat, Prashant V

2014-05-01

Successive ionic layer adsorption and reaction (SILAR) is a popular method of depositing the metal chalcogenide semiconductor layer on the mesoscopic metal oxide films for designing quantum-dot-sensitized solar cells (QDSSCs) or extremely thin absorber (ETA) solar cells. While this deposition method exhibits higher loading of the light-absorbing semiconductor layer than direct adsorption of presynthesized colloidal quantum dots, the chemical identity of these nanostructures and the evolution of interfacial structure are poorly understood. We have now analyzed step-by-step SILAR deposition of CdSe films on mesoscopic TiO2 nanoparticle films using X-ray absorption near-edge structure analysis and probed the interfacial structure of these films. The film characteristics interestingly show dependence on the order in which the Cd and Se are deposited, and the CdSe-TiO2 interface is affected only during the first few cycles of deposition. Development of a SeO2 passivation layer in the SILAR-prepared films to form a TiO2/SeO2/CdSe junction facilitates an increase in photocurrents and power conversion efficiencies of quantum dot solar cells when these films are integrated as photoanodes in a photoelectrochemical solar cell.

Passivation mechanism in silicon heterojunction solar cells with intrinsic hydrogenated amorphous silicon oxide layers

NASA Astrophysics Data System (ADS)

Deligiannis, Dimitrios; van Vliet, Jeroen; Vasudevan, Ravi; van Swaaij, René A. C. M. M.; Zeman, Miro

2017-02-01

In this work, we use intrinsic hydrogenated amorphous silicon oxide layers (a-SiOx:H) with varying oxygen content (cO) but similar hydrogen content to passivate the crystalline silicon wafers. Using our deposition conditions, we obtain an effective lifetime (τeff) above 5 ms for cO ≤ 6 at. % for passivation layers with a thickness of 36 ± 2 nm. We subsequently reduce the thickness of the layers using an accurate wet etching method to ˜7 nm and deposit p- and n-type doped layers fabricating a device structure. After the deposition of the doped layers, τeff appears to be predominantly determined by the doped layers themselves and is less dependent on the cO of the a-SiOx:H layers. The results suggest that τeff is determined by the field-effect rather than by chemical passivation.

Method of fabrication of electrodes and electrolytes

DOEpatents

Jankowski, Alan F.; Morse, Jeffrey D.

2004-01-06

Fuel cell stacks contain an electrolyte layer surrounded on top and bottom by an electrode layer. Porous electrodes are prepared which enable fuel and oxidant to easily flow to the respective electrode-electrolyte interface without the need for high temperatures or pressures to assist the flow. Rigid, inert microspheres in combination with thin-film metal deposition techniques are used to fabricate porous anodes, cathodes, and electrolytes. Microshperes contained in a liquid are randomly dispersed onto a host structure and dried such that the microsperes remain in position. A thin-film deposition technique is subsequently employed to deposit a metal layer onto the microsperes. After such metal layer deposition, the microspheres are removed leaving voids, i.e. pores, in the metal layer, thus forming a porous electrode. Successive repetitions of the fabrication process result in the formation of a continuous fuel cell stack. Such stacks may produce power outputs ranging from about 0.1 Watt to about 50 Watts.

Homogeneous transparent conductive ZnO:Ga by ALD for large LED wafers

NASA Astrophysics Data System (ADS)

Szabó, Zoltán; Baji, Zsófia; Basa, Péter; Czigány, Zsolt; Bársony, István; Wang, Hsin-Ying; Volk, János

2016-08-01

Highly conductive and uniform Ga doped ZnO (GZO) films were prepared by atomic layer deposition (ALD) as transparent conductive layers for InGaN/GaN LEDs. The optimal Ga doping concentration was found to be 3 at%. Even for 4" wafers, the TCO layer shows excellent homogeneity of film resistivity (0.8 %) according to Eddy current and spectroscopic ellipsometry mapping. This makes ALD a favourable technique over concurrent methods like MBE and PLD where the up-scaling is problematic. In agreement with previous studies, it was found that by an annealing treatment the quality of the GZO/p-GaN interface can be improved, although it causes the degradation of TCO conductivity. Therefore, a two-step ALD deposition technique was proposed and demonstrated: a "buffer layer" deposited and annealed first was followed by a second deposition step to maintain the high conductivity of the top layer.

Method of Fabrication of High Power Density Solid Oxide Fuel Cells

DOEpatents

Pham, Ai Quoc; Glass, Robert S.

2008-09-09

A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O(LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

Comparative studies on damages to organic layer during the deposition of ITO films by various sputtering methods

NASA Astrophysics Data System (ADS)

Lei, Hao; Wang, Meihan; Hoshi, Yoichi; Uchida, Takayuki; Kobayashi, Shinichi; Sawada, Yutaka

2013-11-01

Aluminum (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) was respectively bombarded and irradiated by Ar ions, oxygen ions, electron beam and ultraviolet light to confirm damages during the sputter-deposition of transparent conductive oxide (TCO) on organic layer. The degree of damage was evaluated by the photoluminescence (PL) spectra of BAlq. The results confirmed the oxygen ions led to a larger damage and were thought to play the double roles of bombardment to organic layer and reaction with organic layer as well. The comparative studies on PL spectra of BAlq after the deposition of TCO films by various sputtering systems, such as conventional magnetron sputtering (MS), low voltage sputtering (LVS) and kinetic-energy-control-deposition (KECD) system, facing target sputtering (FTS) were performed. Relative to MS, LVS and KECD system, FTS can completely suppress the bombardment of the secondary electrons and oxygen negative ions, and keep a higher deposition rate simultaneously, thus it is a good solution to attain a low-damage sputter-deposition.

The Development of an Environmentally Compliant, Multi-Functional Aerospace Coating Using Molecular- and Nano-Engineering Methods

DTIC Science & Technology

2006-10-02

Al -TM-RE) alloy which could by spray applied using various deposition routes or deposited as a powder that is...corrosion properties of various spray deposited alloys from their properties as defective coatings on 2024-T3. "* HVOF spray deposited and cold spray ...layer. "* A method has been developed to distinguish the intrinsic corrosion properties of various spray deposited

Role of Cu layer thickness on the magnetic anisotropy of pulsed electrodeposited Ni/Cu/Ni tri-layer

NASA Astrophysics Data System (ADS)

Dhanapal, K.; Prabhu, D.; Gopalan, R.; Narayanan, V.; Stephen, A.

2017-07-01

The Ni/Cu/Ni tri-layer film with different thickness of Cu layer was deposited using pulsed electrodeposition method. The XRD pattern of all the films show the formation of fcc structure of nickel and copper. This shows the orientated growth in the (2 2 0) plane of the layered films as calculated from the relative intensity ratio. The layer formation in the films were observed from cross sectional view using FE-SEM and confirms the decrease in Cu layer thickness with decreasing deposition time. The magnetic anisotropy behaviour was measured using VSM with two different orientations of layered film. This shows that increasing anisotropy energy with decreasing Cu layer thickness and a maximum of  -5.13  ×  104 J m-3 is observed for copper deposited for 1 min. From the K eff.t versus t plot, development of perpendicular magnetic anisotropy in the layered system is predicted below 0.38 µm copper layer thickness.

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNamara, Bruce K.; O’Hara, Matthew J.; Casella, Andrew M.

2016-07-01

Abstract: We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other uranium compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within the chamber to a highly predictable degree. We demonstrate the preparation of uranium deposits that range between ~0.01 and 470±34 ng∙cm-2. The data suggest the method can be extended to creating depositions at the sub-picogram∙cm-2 level. Additionally, the isotopic composition of the deposits can be customized by selection of the uranium source materials. Wemore » demonstrate a layering technique whereby two uranium solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit of UF6 that bears an isotopic signature that is a composite of the two uranium sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics.« less

Zinc-oxide-based nanostructured materials for heterostructure solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A., E-mail: vamoshnikov@mail.ru

Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

Dry-spray deposition of TiO2 for a flexible dye-sensitized solar cell (DSSC) using a nanoparticle deposition system (NPDS).

PubMed

Kim, Min-Saeng; Chun, Doo-Man; Choi, Jung-Oh; Lee, Jong-Cheon; Kim, Yang Hee; Kim, Kwang-Su; Lee, Caroline Sunyong; Ahn, Sung-Hoon

2012-04-01

TiO2 powders were deposited on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates for application to the photoelectrode of a dye-sensitized solar cell (DSSC). In the conventional DSSC manufacturing process, a semiconductor oxide such as TiO2 powder requires a sintering process at higher temperature than the glass transition temperature (T(g)) of polymers, and thus utilization of flexible polymer substrates in DSSC research has been constrained. To overcome this restriction related to sintering, we used a nanoparticle deposition system (NPDS) that could produce a thin coating layer through a dry-spray method under atmospheric pressure at room temperature. The powder was sprayed through a slit-type nozzle having a 0.4 x 10 mm2 rectangular outlet. In order to determine the deposited TiO2 thickness, five kinds of TiO2 layered specimens were prepared, where the specimens have single and double layer structures. Deposited powders on the ITO coated PET substrates were observed using FE-SEM and a scan profiler The thicker TiO2 photoelectrode with a DSSC having a double layer structure showed higher energy efficiency than the single layer case. The highest fabricated flexible DSSC displayed a short circuit current density J(sc) = 1.99 mA cm(-2), open circuit voltage V(oc) = 0.71 V, and energy efficiency eta = 0.94%. These results demonstrate the possibility of utilizing the dry-spray method to fabricate a TiO2 layer on flexible polymer substrates at room temperature under atmospheric pressure.

Epitaxial GaN layers formed on langasite substrates by the plasma-assisted MBE method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobanov, D. N., E-mail: dima@ipmras.ru; Novikov, A. V.; Yunin, P. A.

2016-11-15

In this publication, the results of development of the technology of the epitaxial growth of GaN on single-crystal langasite substrates La{sub 3}Ga{sub 5}SiO{sub 14} (0001) by the plasma-assisted molecular-beam epitaxy (PA MBE) method are reported. An investigation of the effect of the growth temperature at the initial stage of deposition on the crystal quality and morphology of the obtained GaN layer is performed. It is demonstrated that the optimal temperature for deposition of the initial GaN layer onto the langasite substrate is about ~520°C. A decrease in the growth temperature to this value allows the suppression of oxygen diffusion frommore » langasite into the growing layer and a decrease in the dislocation density in the main GaN layer upon its subsequent high-temperature deposition (~700°C). Further lowering of the growth temperature of the nucleation layer leads to sharp degradation of the GaN/LGS layer crystal quality. As a result of the performed research, an epitaxial GaN/LGS layer with a dislocation density of ~10{sup 11} cm{sup –2} and low surface roughness (<2 nm) is obtained.« less

CVD aluminiding process for producing a modified platinum aluminide bond coat for improved high temperature performance

NASA Technical Reports Server (NTRS)

Nagaraj, Bangalore A. (Inventor); Williams, Jeffrey L. (Inventor)

2003-01-01

A method of depositing by chemical vapor deposition a modified platinum aluminide diffusion coating onto a superalloy substrate comprising the steps of applying a layer of a platinum group metal to the superalloy substrate; passing an externally generated aluminum halide gas through an internal gas generator which is integral with a retort, the internal gas generator generating a modified halide gas; and co-depositing aluminum and modifier onto the superalloy substrate. In one form, the modified halide gas is hafnium chloride and the modifier is hafnium with the modified platinum aluminum bond coat comprising a single phase additive layer of platinum aluminide with at least about 0.5 percent hafnium by weight percent and about 1 to about 15 weight percent of hafnium in the boundary between a diffusion layer and the additive layer. The bond coat produced by this method is also claimed.

Functionalized graphene-Pt composites for fuel cells and photoelectrochemical cells

DOEpatents

Diankov, Georgi; An, Jihwan; Park, Joonsuk; Goldhaber, David J. K.; Prinz, Friedrich B.

2017-08-29

A method of growing crystals on two-dimensional layered material is provided that includes reversibly hydrogenating a two-dimensional layered material, using a controlled radio-frequency hydrogen plasma, depositing Pt atoms on the reversibly hydrogenated two-dimensional layered material, using Atomic Layer Deposition (ALD), where the reversibly hydrogenated two-dimensional layered material promotes loss of methyl groups in an ALD Pt precursor, and forming Pt-O on the reversibly hydrogenated two-dimensional layered material, using combustion by O.sub.2, where the Pt-O is used for subsequent Pt half-cycles of the ALD process, where growth of Pt crystals occurs.

Novel procedure to enhance PLA surface properties by chitosan irreversible immobilization

NASA Astrophysics Data System (ADS)

Stoleru, Elena; Dumitriu, Raluca Petronela; Munteanu, Bogdanel Silvestru; Zaharescu, Traian; Tănase, Elisabeta Elena; Mitelut, Amalia; Ailiesei, Gabriela-Liliana; Vasile, Cornelia

2016-03-01

A novel two step procedure was applied for poly(lactic acid) (PLA) functionalization consisting in the exposure to cold radiofrequency plasma in nitrogen atmosphere or to gamma irradiation followed by ;grafting to; of a chitosan layer using carbodiimide chemistry. The adhesion and stability of the deposited surface layer was assured by plasma/gamma irradiation treatment while the chitosan layer offers antifungal/antibacterial/antioxidant activities. Chitosan with different viscosities/deacetylation degree was deposited by electrospinning or immersion methods. Correlations between rheological behavior of chitosan solutions and chitosan layer deposition conditions are made. The PLA surface properties were investigated by water contact angle measurements, ATR-FTIR spectroscopy, AFM, chemiluminiscence, etc. It has been established that the surface roughness increases direct proportional with cold plasma duration and gamma irradiation dose and further increases by chitosan coating which at its turn depends on chitosan characteristics (viscosity and deacetylation degree) and method of deposition. Nano-fibers with relatively homogeneous and reproducible features are obtained by electrospinning of highly viscous chitosan while with the other two types of chitosan both microparticles and nano-fibers are formed. The chitosan coating obtained by immersion is more homogenous and compact and has a better antibacterial activity than the electrospun layer as fiber meshes.

Part height control of laser metal additive manufacturing process

NASA Astrophysics Data System (ADS)

Pan, Yu-Herng

Laser Metal Deposition (LMD) has been used to not only make but also repair damaged parts in a layer-by-layer fashion. Parts made in this manner may produce less waste than those made through conventional machining processes. However, a common issue of LMD involves controlling the deposition's layer thickness. Accuracy is important, and as it increases, both the time required to produce the part and the material wasted during the material removal process (e.g., milling, lathe) decrease. The deposition rate is affected by multiple parameters, such as the powder feed rate, laser input power, axis feed rate, material type, and part design, the values of each of which may change during the LMD process. Using a mathematical model to build a generic equation that predicts the deposition's layer thickness is difficult due to these complex parameters. In this thesis, we propose a simple method that utilizes a single device. This device uses a pyrometer to monitor the current build height, thereby allowing the layer thickness to be controlled during the LMD process. This method also helps the LMD system to build parts even with complex parameters and to increase material efficiency.

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method.

PubMed

McNamara, Bruce K; O'Hara, Matthew J; Casella, Andrew M; Carter, Jennifer C; Addleman, R Shane; MacFarlan, Paul J

2016-07-01

We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other U compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within a fixed reactor geometry to a highly predictable degree. We demonstrate the preparation of U deposits that range between approximately 0.01 and 500ngcm(-2). The data suggest the method can be extended to creating depositions at the sub-picogramcm(-2) level. The isotopic composition of the deposits can be customized by selection of the U source materials and we demonstrate a layering technique whereby two U solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit that bears an isotopic signature that is a composite of the two U sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics. Further, the method allows access to very low atomic or molecular coverages of surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

Method for high-precision multi-layered thin film deposition for deep and extreme ultraviolet mirrors

DOEpatents

Ruffner, Judith Alison

1999-01-01

A method for coating (flat or non-flat) optical substrates with high-reflectivity multi-layer coatings for use at Deep Ultra-Violet ("DUV") and Extreme Ultra-Violet ("EUV") wavelengths. The method results in a product with minimum feature sizes of less than 0.10-.mu.m for the shortest wavelength (13.4-nm). The present invention employs a computer-based modeling and deposition method to enable lateral and vertical thickness control by scanning the position of the substrate with respect to the sputter target during deposition. The thickness profile of the sputter targets is modeled before deposition and then an appropriate scanning algorithm is implemented to produce any desired, radially-symmetric thickness profile. The present invention offers the ability to predict and achieve a wide range of thickness profiles on flat or figured substrates, i.e., account for 1/R.sup.2 factor in a model, and the ability to predict and accommodate changes in deposition rate as a result of plasma geometry, i.e., over figured substrates.

Oxidized film structure and method of making epitaxial metal oxide structure

DOEpatents

Gan, Shupan [Richland, WA; Liang, Yong [Richland, WA

2003-02-25

A stable oxidized structure and an improved method of making such a structure, including an improved method of making an interfacial template for growing a crystalline metal oxide structure, are disclosed. The improved method comprises the steps of providing a substrate with a clean surface and depositing a metal on the surface at a high temperature under a vacuum to form a metal-substrate compound layer on the surface with a thickness of less than one monolayer. The compound layer is then oxidized by exposing the compound layer to essentially oxygen at a low partial pressure and low temperature. The method may further comprise the step of annealing the surface while under a vacuum to further stabilize the oxidized film structure. A crystalline metal oxide structure may be subsequently epitaxially grown by using the oxidized film structure as an interfacial template and depositing on the interfacial template at least one layer of a crystalline metal oxide.

Technologies for deposition of transition metal oxide thin films: application as functional layers in “Smart windows” and photocatalytic systems

NASA Astrophysics Data System (ADS)

Gesheva, K.; Ivanova, T.; Bodurov, G.; Szilágyi, I. M.; Justh, N.; Kéri, O.; Boyadjiev, S.; Nagy, D.; Aleksandrova, M.

2016-02-01

“Smart windows” are envisaged for future low-energy, high-efficient architectural buildings, as well as for the car industry. By switching from coloured to fully bleached state, these windows regulate the energy of solar flux entering the interior. Functional layers in these devices are the transition metals oxides. The materials (transitional metal oxides) used in smart windows can be also applied as photoelectrodes in water splitting photocells for hydrogen production or as photocatalytic materials for self-cleaning surfaces, waste water treatment and pollution removal. Solar energy utilization is recently in the main scope of numerous world research laboratories and energy organizations, working on protection against conventional fuel exhaustion. The paper presents results from research on transition metal oxide thin films, fabricated by different methods - atomic layer deposition, atmospheric pressure chemical vapour deposition, physical vapour deposition, and wet chemical methods, suitable for flowthrough production process. The lower price of the chemical deposition processes is especially important when the method is related to large-scale glazing applications. Conclusions are derived about which processes are recently considered as most prospective, related to electrochromic materials and devices manufacturing.

Effect of starting powder morphology on film texture for bismuth layer-structured ferroelectrics prepared by aerosol deposition method

NASA Astrophysics Data System (ADS)

Suzuki, Muneyasu; Tsuchiya, Tetsuo; Akedo, Jun

2017-06-01

We report grain orientation control for bismuth layer-structured ferroelectrics (BLSFs) films deposited by aerosol deposition (AD) method at room temperature. Bi4Ti3O12 (BiT), SrBi2Ta2O9 (SBTa), and SrBi4Ti4O15 (SBTi) starting powders with particles of various shape (plate-like, spherical, and angular) were prepared by solid-state reaction and fused salt synthesis. Their AD films represented fine microstructures without pores, which agrees well with previous reports. Although the SBTa AD films deposited by using spherical particles exhibited an extremely low Lotgering factor (F), the BiT AD films deposited by using plate-like particles exhibited a marked c-axis orientation. The F of BiT and SBTi AD films decreased with increasing film thickness (t). We consider that the dispersion of agglomerated plate-like particles on the film surface and the densification of the compacted powder layer occurring while under particle impact are important in obtaining the grain-oriented AD films. These results of using the AD method with shape-controlled particles are expected to result in open up an innovative functional coating technique.

Magnetostriction measurement of a giant magnetoresistance film on a practical substrate covered by a shield layer

NASA Astrophysics Data System (ADS)

Okita, Kazuhiko; Ishiyama, Kazushi; Miura, Hideo

2012-04-01

Magnetostriction constant of a magnetic thin film is conventionally measured by detecting the deformation of a coupon sample that consists of the magnetic film deposited on a thin glass substrate (e.g., cover glass of size 10 mm × 25 mm) under an applied field using a laser beam [A. C. Tam and H. Schroeder, J. Appl. Phys. 64, 5422 (1988)]. This method, however, cannot be applied to films deposited on actual large-size substrates (wafers) with diameter from 3 to 6 in. or more. In a previous paper [Okita et al., J. Phys.: Conf. Ser. 200, 112008 (2010)], the authors presented a method for measuring magnetostriction of a magnetic thin film deposited on an actual substrate by detecting the change of magnetic anisotropy field, Hk, under mechanical bending of the substrate. It was validated that the method is very effective for measuring the magnetostriction constant of a free layer on the actual substrate. However, since a Ni-Fe shield layer usually covers a magnetic head used for a hard disk drive, this shield layer disturbs the effective measurement of R-H curve under minor loop. Therefore, a high magnetic field that can saturate the magnetic material in the shield layer should be applied to the head in order to measure the magnetostriction constant of a pinned layer under the shield layer. In this paper, this method was applied to the measurement of the magnetostriction constant of a pinned layer under the shield layer by using a high magnetic field up to 320 kA/m (4 kOe).

Formation of a Crack-Free, Hybrid Skin Layer with Tunable Surface Topography and Improved Gas Permeation Selectivity on Elastomers Using Gel–Liquid Infiltration Polymerization

DOE PAGES

Wang, Mengyuan; Gorham, Justin M.; Killgore, Jason P.; ...

2017-07-31

Surface modifications of elastomers and gels are crucial for emerging applications such as soft robotics and flexible electronics, in large part because they provide a platform to control wettability, adhesion, and permeability. Current surface modification methods via ultraviolet-ozone (UVO) and/or O2 plasma, atomic layer deposition (ALD), plasmas deposition, and chemical treatment impart a dense polymer or inorganic layer on the surface that is brittle and easy to fracture at low strain levels. This paper presents a new method, based on gel–liquid infiltration polymerization, to form hybrid skin layers atop elastomers. The method is unique in that it allows for controlmore » of the skin layer topography, with tunable feature sizes and aspect ratios as high as 1.8 without fracture. Unlike previous techniques, the skin layer formed here dramatically improves the barrier properties of the elastomer, while preserving skin layer flexibility. Furthermore, the method is versatile and likely applicable to most interfacial polymerization systems and network polymers on flat and patterned surfaces.« less

Formation of a Crack-Free, Hybrid Skin Layer with Tunable Surface Topography and Improved Gas Permeation Selectivity on Elastomers Using Gel–Liquid Infiltration Polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Mengyuan; Gorham, Justin M.; Killgore, Jason P.

Surface modifications of elastomers and gels are crucial for emerging applications such as soft robotics and flexible electronics, in large part because they provide a platform to control wettability, adhesion, and permeability. Current surface modification methods via ultraviolet-ozone (UVO) and/or O2 plasma, atomic layer deposition (ALD), plasmas deposition, and chemical treatment impart a dense polymer or inorganic layer on the surface that is brittle and easy to fracture at low strain levels. This paper presents a new method, based on gel–liquid infiltration polymerization, to form hybrid skin layers atop elastomers. The method is unique in that it allows for controlmore » of the skin layer topography, with tunable feature sizes and aspect ratios as high as 1.8 without fracture. Unlike previous techniques, the skin layer formed here dramatically improves the barrier properties of the elastomer, while preserving skin layer flexibility. Furthermore, the method is versatile and likely applicable to most interfacial polymerization systems and network polymers on flat and patterned surfaces.« less

Determination of defect content and defect profile in semiconductor heterostructures

NASA Astrophysics Data System (ADS)

Zubiaga, A.; Garcia, J. A.; Plazaola, F.; Zúñiga-Pérez, J.; Muñoz-Sanjosé, V.

2011-01-01

In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

High efficiency diamond solar cells

DOEpatents

Gruen, Dieter M [Downers Grove, IL

2008-05-06

A photovoltaic device and method of making same. A layer of p-doped microcrystalline diamond is deposited on a layer of n-doped ultrananocrystalline diamond such as by providing a substrate in a chamber, providing a first atmosphere containing about 1% by volume CH.sub.4 and about 99% by volume H.sub.2 with dopant quantities of a boron compound, subjecting the atmosphere to microwave energy to deposit a p-doped microcrystalline diamond layer on the substrate, providing a second atmosphere of about 1% by volume CH.sub.4 and about 89% by volume Ar and about 10% by volume N.sub.2, subjecting the second atmosphere to microwave energy to deposit a n-doped ultrananocrystalline diamond layer on the p-doped microcrystalline diamond layer. Electrodes and leads are added to conduct electrical energy when the layers are irradiated.

Electroless deposition process for zirconium and zirconium alloys

DOEpatents

Donaghy, R. E.; Sherman, A. H.

1981-08-18

A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer. 1 fig.

Electroless deposition process for zirconium and zirconium alloys

DOEpatents

Donaghy, Robert E.; Sherman, Anna H.

1981-01-01

A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer.

Thermoelectric material including conformal oxide layers and method of making the same using atomic layer deposition

DOEpatents

Cho, Jung Young; Ahn, Dongjoon; Salvador, James R.; Meisner, Gregory P.

2016-06-07

A thermoelectric material includes a substrate particle and a plurality of conformal oxide layers formed on the substrate particle. The plurality of conformal oxide layers has a total oxide layer thickness ranging from about 2 nm to about 20 nm. The thermoelectric material excludes oxide nanoparticles. A method of making the thermoelectric material is also disclosed herein.

Cosine (Cobalt Silicide Growth Through Nitrogen-Induced Epitaxy) Process For Epitaxial Cobalt Silicide Formation For High Performance Sha

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Chong Wee; Shin, Chan Soo; Gall, Daniel

A method for forming an epitaxial cobalt silicide layer on a MOS device includes sputter depositing cobalt in an ambient to form a first layer of cobalt suicide on a gate and source/drain regions of the MOS device. Subsequently, cobalt is sputter deposited again in an ambient of argon to increase the thickness of the cobalt silicide layer to a second thickness.

IZO deposited by PLD on flexible substrate for organic heterostructures

NASA Astrophysics Data System (ADS)

Socol, M.; Preda, N.; Stanculescu, A.; Breazu, C.; Florica, C.; Rasoga, O.; Stanculescu, F.; Socol, G.

2017-05-01

In:ZnO (IZO) thin films were deposited on flexible plastic substrates by pulsed laser deposition (PLD) method. The obtained layers present adequate optical and electrical properties competitive with those based on indium tin oxide (ITO). The figure of merit (9 × 10-3 Ω-1) calculated for IZO layers demonstrates that high quality coatings can be prepared by this deposition technique. A thermal annealing (150 °C for 1 h) or an oxygen plasma etching (6 mbar for 10 min.) were applied to the IZO layers to evaluate the influence of these treatments on the properties of the transparent coatings. Using vacuum evaporation, organic heterostructures based on cooper phthalocyanine (CuPc) and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) were deposited on the untreated and treated IZO layers. The optical and electrical properties of the heterostructures were investigated by UV-Vis, FTIR and current-voltage ( I- V) measurements. For the heterostructure fabricated on IZO treated in oxygen plasma, an improvement in the current value with at least one order of magnitude was evidenced in the I- V characteristics recorded in dark conditions. Also, an increase in the current value for the heterostructure deposited on untreated IZO layer can be achieved by adding an organic layer such as tris-8-hydroxyquinoline aluminium (Alq3).

Acoustic resonator and method of making same

DOEpatents

Kline, Gerald R.; Lakin, Kenneth M.

1985-03-05

A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.

Acoustic resonator and method of making same

DOEpatents

Kline, G.R.; Lakin, K.M.

1983-10-13

A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.

Methods for producing thin film charge selective transport layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, Scott Ryan; Olson, Dana C.; van Hest, Marinus Franciscus Antonius Maria

Methods for producing thin film charge selective transport layers are provided. In one embodiment, a method for forming a thin film charge selective transport layer comprises: providing a precursor solution comprising a metal containing reactive precursor material dissolved into a complexing solvent; depositing the precursor solution onto a surface of a substrate to form a film; and forming a charge selective transport layer on the substrate by annealing the film.

Method of manufacturing semiconductor having group II-group VI compounds doped with nitrogen

DOEpatents

Compaan, Alvin D.; Price, Kent J.; Ma, Xianda; Makhratchev, Konstantin

2005-02-08

A method of making a semiconductor comprises depositing a group II-group VI compound onto a substrate in the presence of nitrogen using sputtering to produce a nitrogen-doped semiconductor. This method can be used for making a photovoltaic cell using sputtering to apply a back contact layer of group II-group VI compound to a substrate in the presence of nitrogen, the back coating layer being doped with nitrogen. A semiconductor comprising a group II-group VI compound doped with nitrogen, and a photovoltaic cell comprising a substrate on which is deposited a layer of a group II-group VI compound doped with nitrogen, are also included.

High power density solid oxide fuel cells

DOEpatents

Pham, Ai Quoc; Glass, Robert S.

2004-10-12

A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

Chemical vapor deposition of sialon

DOEpatents

Landingham, R.L.; Casey, A.W.

A laminated composite and a method for forming the composite by chemical vapor deposition are described. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200/sup 0/C; and impinging a gas containing N/sub 2/, SiCl/sub 4/, and AlCl/sub 3/ on the surface.

Electro-deposition of superconductor oxide films

DOEpatents

Bhattacharya, Raghu N.

2001-01-01

Methods for preparing high quality superconducting oxide precursors which are well suited for further oxidation and annealing to form superconducting oxide films. The method comprises forming a multilayered superconducting precursor on a substrate by providing an electrodeposition bath comprising an electrolyte medium and a substrate electrode, and providing to the bath a plurality of precursor metal salts which are capable of exhibiting superconducting properties upon subsequent treatment. The superconducting precursor is then formed by electrodepositing a first electrodeposited (ED) layer onto the substrate electrode, followed by depositing a layer of silver onto the first electrodeposited (ED) layer, and then electrodepositing a second electrodeposited (ED) layer onto the Ag layer. The multilayered superconducting precursor is suitable for oxidation at a sufficient annealing temperature in air or an oxygen-containing atmosphere to form a crystalline superconducting oxide film.

Crystalline ha coating on peek via chemical deposition

NASA Astrophysics Data System (ADS)

Almasi, D.; Izman, S.; Assadian, M.; Ghanbari, M.; Abdul Kadir, M. R.

2014-09-01

Polyether ether ketone (PEEK) has a similar elastic modulus to bone and can be a suitable alternative to metallic implants. However, PEEK is bioinert and does not integrate well with the surrounding tissues. The current commercial method for solving this problem is by coating PEEK substrates with calcium phosphates via plasma spraying. However, this method produces a low bonding strength between the substrate and the coating layer, as well as non-uniform density of the coating. In this study, chemical deposition was used to deposit HA crystalline particles on PEEK substrate without any subsequent crystallisation process therefore producing crystalline treated layer. EDX results confirmed the deposition of HA, and the XRD results confirmed that the treated layer was crystalline HA. FT-IR analysis confirmed the chemical bonding between HA and the substrate. Surface roughness increased from 24.27 nm to 34.08 nm for 3 min immersion time. The water contact angle showed an increase in wettability of the treated sample from 71.6 to 36.4 degrees, which in turn increased its bioactivity. The proposed method is a suitable alternative to other conventional methods as high temperature was not involved in the process which could damage the surface of the substrate.

Low-stress silicon nitride layers for MEMS applications

NASA Astrophysics Data System (ADS)

Iliescu, Ciprian; Wei, Jiashen; Chen, Bangtao; Ong, Poh Lam; Tay, Francis E. H.

2006-12-01

The paper presents two deposition methods for generation of SiN x layers with "zero" residual stress in PECVD reactors: mixed frequency and high power in high frequency mode (13.56 MHz). Traditionally, mix frequency mode is commonly used to produce low stress SiN x layers, which alternatively applies the HF and LF mode. However, due to the low deposition rate of LF mode, the combined deposition rate of mix frequency is quite small in order to produce homogenous SiN x layers. In the second method, a high power which was up to 600 W has been used, may also produce low residual stress (0-20 MPa), with higher deposition rate (250 to 350 nm/min). The higher power not only leads to higher dissociation rates of gases which results in higher deposition rates, but also brings higher N bonding in the SiN x films and higher compressive stress from higher volume expansion of SiN x films, which compensates the tensile stress and produces low residual stress. In addition, the paper investigates the influence of other important parameters which have great impact to the residual stress and deposition rates, such as reactant gases flow rate and pressure. By using the final optimized recipe, masking layer for anisotropic wet etching in KOH and silicon nitride cantilever have been successfully fabricated based on the low stress SiN x layers. Moreover, nanoporous membrane with 400nm pores has also been fabricated and tested for cell culture. By cultivating the mouse D1 mesenchymal stem cells on top of the nanoporous membrane, the results showed that mouse D1 mesenchymal stem cells were able to grow well. This shows that the nanoporous membrane can be used as the platform for interfacing with living cells to become biocapsules for biomolecular separation.

Photoluminescence of Ta2O5 films formed by the molecular layer deposition method

NASA Astrophysics Data System (ADS)

Baraban, A. P.; Dmitriev, V. A.; Prokof'ev, V. A.; Drozd, V. E.; Filatova, E. O.

2016-04-01

Ta2O5 films of different thicknesses (20-100 nm) synthesized by the molecular layer deposition method on p-type silicon substrates and thermally oxidized silicon substrates have been studied by the methods of high-frequency capacitance-voltage characteristics and photoluminescence. A hole-conduction channel is found to form in the Si-Ta2O5-field electrode system. A model of the electronic structure of Ta2O5 films is proposed based on an analysis of the measured PL spectra and performed electrical investigations.

Deposition method for producing silicon carbide high-temperature semiconductors

DOEpatents

Hsu, George C.; Rohatgi, Naresh K.

1987-01-01

An improved deposition method for producing silicon carbide high-temperature semiconductor material comprising placing a semiconductor substrate composed of silicon carbide in a fluidized bed silicon carbide deposition reactor, fluidizing the bed particles by hydrogen gas in a mildly bubbling mode through a gas distributor and heating the substrate at temperatures around 1200.degree.-1500.degree. C. thereby depositing a layer of silicon carbide on the semiconductor substrate.

Method of fabricating germanium and gallium arsenide devices

NASA Technical Reports Server (NTRS)

Jhabvala, Murzban (Inventor)

1990-01-01

A method of semiconductor diode fabrication is disclosed which relies on the epitaxial growth of a precisely doped thickness layer of gallium arsenide or germanium on a semi-insulating or intrinsic substrate, respectively, of gallium arsenide or germanium by either molecular beam epitaxy (MBE) or by metal-organic chemical vapor deposition (MOCVD). The method involves: depositing a layer of doped or undoped silicon dioxide on a germanium or gallium arsenide wafer or substrate, selectively removing the silicon dioxide layer to define one or more surface regions for a device to be fabricated thereon, growing a matched epitaxial layer of doped germanium or gallium arsenide of an appropriate thickness using MBE or MOCVD techniques on both the silicon dioxide layer and the defined one or more regions; and etching the silicon dioxide and the epitaxial material on top of the silicon dioxide to leave a matched epitaxial layer of germanium or gallium arsenide on the germanium or gallium arsenide substrate, respectively, and upon which a field effect device can thereafter be formed.

Method for making biaxially textured articles by plastic deformation

DOEpatents

Goyal, Amit

2002-01-01

A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.

Aligned carbon nanotube, graphene and graphite oxide thin films via substrate-directed rapid interfacial deposition

NASA Astrophysics Data System (ADS)

D'Arcy, Julio M.; Tran, Henry D.; Stieg, Adam Z.; Gimzewski, James K.; Kaner, Richard B.

2012-05-01

A procedure for depositing thin films of carbon nanostructures is described that overcomes the limitations typically associated with solution based methods. Transparent and conductively continuous carbon coatings can be grown on virtually any type of substrate within seconds. Interfacial surface tension gradients result in directional fluid flow and film spreading at the water/oil interface. Transparent films of carbon nanostructures are produced including aligned ropes of single-walled carbon nanotubes and assemblies of single sheets of chemically converted graphene and graphite oxide. Process scale-up, layer-by-layer deposition, and a simple method for coating non-activated hydrophobic surfaces are demonstrated.A procedure for depositing thin films of carbon nanostructures is described that overcomes the limitations typically associated with solution based methods. Transparent and conductively continuous carbon coatings can be grown on virtually any type of substrate within seconds. Interfacial surface tension gradients result in directional fluid flow and film spreading at the water/oil interface. Transparent films of carbon nanostructures are produced including aligned ropes of single-walled carbon nanotubes and assemblies of single sheets of chemically converted graphene and graphite oxide. Process scale-up, layer-by-layer deposition, and a simple method for coating non-activated hydrophobic surfaces are demonstrated. Electronic supplementary information (ESI) available: Droplet coalescence, catenoid formation, mechanism of film growth, scanning electron micrographs showing carbon nanotube alignment, flexible transparent films of SWCNTs, AFM images of a chemically converted graphene film, and SEM images of SWCNT free-standing thin films. See DOI: 10.1039/c2nr00010e

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benson, David M.; Tsang, Chu F.; Sugar, Joshua Daniel

One method for the formation of nanofilms of materials, is Electrochemical atomic layer deposition (E-ALD), one atomic layer at a time. It uses the galvanic exchange of a less noble metal, deposited using underpotential deposition (UPD), to produce an atomic layer of a more noble element by reduction of its ions. This process is referred to as surface limited redox replacement and can be repeated in a cycle to grow thicker deposits. Previously, we performed it on nanoparticles and planar substrates. In the present report, E-ALD is applied for coating a submicron-sized powder substrate, making use of a new flowmore » cell design. E-ALD is used to coat a Pd powder substrate with different thicknesses of Rh by exchanging it for Cu UPD. Furthermore, cyclic voltammetry and X-ray photoelectron spectroscopy indicate an increasing Rh coverage with increasing numbers of deposition cycles performed, in a manner consistent with the atomic layer deposition (ALD) mechanism. Cyclic voltammetry also indicated increased kinetics of H sorption and desorption in and out of the Pd powder with Rh present, relative to unmodified Pd.« less

Morphologies, microstructures, and mechanical properties of samples produced using laser metal deposition with 316 L stainless steel wire

NASA Astrophysics Data System (ADS)

Xu, Xiang; Mi, Gaoyang; Luo, Yuanqing; Jiang, Ping; Shao, Xinyu; Wang, Chunming

2017-07-01

Laser metal deposition (LMD) with a filler has been demonstrated to be an effective method for additive manufacturing because of its high material deposition efficiency, improved surface quality, reduced material wastage, and cleaner process environment without metal dust pollution. In this study, single beads and samples with ten layers were successfully deposited on a 316 L stainless steel surface under optimized conditions using a 4000 W continuous wave fibre laser and an arc welding machine. The results showed that satisfactory layered samples with a large deposition height and smooth side surface could be achieved under appropriate parameters. The uniform structures had fine cellular and network austenite grains with good metallurgical bonding between layers, showing an austenite solidification mode. Precipitated ferrite at the grain boundaries showed a subgrain structure with fine uniform grain size. A higher microhardness (205-226 HV) was detected in the middle of the deposition area, while the tensile strength of the 50 layer sample reached 669 MPa. In addition, ductile fracturing was proven by the emergence of obvious dimples at the fracture surface.

Use of separate ZnTe interface layers to form ohmic contacts to p-CdTe films

DOEpatents

Gessert, T.A.

1999-06-01

A method of is disclosed improving electrical contact to a thin film of a p-type tellurium-containing II-VI semiconductor comprising: depositing a first undoped layer of ZnTe on a thin film of p-type tellurium containing II-VI semiconductor with material properties selected to limit the formation of potential barriers at the interface between the p-CdTe and the undoped layer, to a thickness sufficient to control diffusion of the metallic-doped ZnTe into the p-type tellurium-containing II-VI semiconductor, but thin enough to minimize affects of series resistance; depositing a second heavy doped p-type ZnTe layer to the first layer using an appropriate dopant; and depositing an appropriate metal onto the outer-most surface of the doped ZnTe layer for connecting an external electrical conductor to an ohmic contact. 11 figs.

Use of separate ZnTe interface layers to form OHMIC contacts to p-CdTe films

DOEpatents

Gessert, Timothy A.

1999-01-01

A method of improving electrical contact to a thin film of a p-type tellurium-containing II-VI semiconductor comprising: depositing a first undoped layer of ZnTe on a thin film of p-type tellurium containing II-VI semiconductor with material properties selected to limit the formation of potential barriers at the interface between the p-CdTe and the undoped layer, to a thickness sufficient to control diffusion of the metallic-doped ZnTe into the p-type tellurim-containing II-VI semiconductor, but thin enough to minimize affects of series resistance; depositing a second heavy doped p-type ZnTe layer to the first layer using an appropriate dopant; and depositing an appropriate metal onto the outer-most surface of the doped ZnTe layer for connecting an external electrical conductor to an ohmic contact.

Acoustic resonator and method of making same

DOEpatents

Kline, G.R.; Lakin, K.M.

1985-03-05

A method is disclosed of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers. 4 figs.

A Method to Predict the Thickness of Poorly-Bonded Material Along Spray and Spray-Layer Boundaries in Cold Spray Deposition

NASA Astrophysics Data System (ADS)

Li, Yangfan; Hamada, Yukitaka; Otobe, Katsunori; Ando, Teiichi

2017-02-01

Multi-traverse CS provides a unique means for the production of thick coatings and bulk materials from powders. However, the material along spray and spray-layer boundaries is often poorly bonded as it is laid by the leading and trailing peripheries of the spray that carry powder particles with insufficient kinetic energy. For the same reason, the splats in the very first layer deposited on the substrate may not be bonded well either. A mathematical spray model was developed based on an axisymmetric Gaussian mass flow rate distribution and a stepped deposition yield to predict the thickness of such poorly-bonded layers in multi-traverse CS deposition. The predicted thickness of poorly-bonded layers in a multi-traverse Cu coating falls in the range of experimental values. The model also predicts that the material that contains poorly bonded splats could exceed 20% of the total volume of the coating.

Methods of electrophoretic deposition for functionally graded porous nanostructures and systems thereof

DOEpatents

Worsley, Marcus A; Baumann, Theodore F; Satcher, Joe H; Olson, Tammy Y; Kuntz, Joshua D; Rose, Klint A

2015-03-03

In one embodiment, an aerogel includes a layer of shaped particles having a particle packing density gradient in a thickness direction of the layer, wherein the shaped particles are characterized by being formed in an electrophoretic deposition (EPD) process using an impurity. In another embodiment, a method for forming a functionally graded porous nanostructure includes adding particles of an impurity and a solution to an EPD chamber, applying a voltage difference across the two electrodes of the EPD chamber to create an electric field in the EPD chamber, and depositing the material onto surfaces of the particles of the impurity to form shaped particles of the material. Other functionally graded materials and methods are described according to more embodiments.

Developments of the Physical and Electrical Properties of NiCr and NiCrSi Single-Layer and Bi-Layer Nano-Scale Thin-Film Resistors.

PubMed

Cheng, Huan-Yi; Chen, Ying-Chung; Li, Chi-Lun; Li, Pei-Jou; Houng, Mau-Phon; Yang, Cheng-Fu

2016-02-25

In this study, commercial-grade NiCr (80 wt % Ni, 20 wt % Cr) and NiCrSi (55 wt % Ni, 40 wt % Cr, 5 wt % Si) were used as targets and the sputtering method was used to deposit NiCr and NiCrSi thin films on Al₂O₃ and Si substrates at room temperature under different deposition time. X-ray diffraction patterns showed that the NiCr and NiCrSi thin films were amorphous phase, and the field-effect scanning electronic microscope observations showed that only nano-crystalline grains were revealed on the surfaces of the NiCr and NiCrSi thin films. The log (resistivity) values of the NiCr and NiCrSi thin-film resistors decreased approximately linearly as their thicknesses increased. We found that the value of temperature coefficient of resistance (TCR value) of the NiCr thin-film resistors was positive and that of the NiCrSi thin-film resistors was negative. To investigate these thin-film resistors with a low TCR value, we designed a novel bi-layer structure to fabricate the thin-film resistors via two different stacking methods. The bi-layer structures were created by depositing NiCr for 10 min as the upper (or lower) layer and depositing NiCrSi for 10, 30, or 60 min as the lower (or upper) layer. We aim to show that the stacking method had no apparent effect on the resistivity of the NiCr-NiCrSi bi-layer thin-film resistors but had large effect on the TCR value.

Developments of the Physical and Electrical Properties of NiCr and NiCrSi Single-Layer and Bi-Layer Nano-Scale Thin-Film Resistors

PubMed Central

Cheng, Huan-Yi; Chen, Ying-Chung; Li, Chi-Lun; Li, Pei-Jou; Houng, Mau-Phon; Yang, Cheng-Fu

2016-01-01

In this study, commercial-grade NiCr (80 wt % Ni, 20 wt % Cr) and NiCrSi (55 wt % Ni, 40 wt % Cr, 5 wt % Si) were used as targets and the sputtering method was used to deposit NiCr and NiCrSi thin films on Al2O3 and Si substrates at room temperature under different deposition time. X-ray diffraction patterns showed that the NiCr and NiCrSi thin films were amorphous phase, and the field-effect scanning electronic microscope observations showed that only nano-crystalline grains were revealed on the surfaces of the NiCr and NiCrSi thin films. The log (resistivity) values of the NiCr and NiCrSi thin-film resistors decreased approximately linearly as their thicknesses increased. We found that the value of temperature coefficient of resistance (TCR value) of the NiCr thin-film resistors was positive and that of the NiCrSi thin-film resistors was negative. To investigate these thin-film resistors with a low TCR value, we designed a novel bi-layer structure to fabricate the thin-film resistors via two different stacking methods. The bi-layer structures were created by depositing NiCr for 10 min as the upper (or lower) layer and depositing NiCrSi for 10, 30, or 60 min as the lower (or upper) layer. We aim to show that the stacking method had no apparent effect on the resistivity of the NiCr-NiCrSi bi-layer thin-film resistors but had large effect on the TCR value. PMID:28344296

Method for deposition of a conductor in integrated circuits

DOEpatents

Creighton, J. Randall; Dominguez, Frank; Johnson, A. Wayne; Omstead, Thomas R.

1997-01-01

A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten.

The comparison of phosphate-titanate-silicate layers on the titanium and Ti6Al4V alloy base.

PubMed

Rokita, M

2011-08-15

The studied layers were composed of two parts: titanate-silicate underlayer for better adhesion and titanate-phosphate-silicate layers for potential bioparameters. The layers with different amounts of hydroxyapatite were deposited on titanium and Ti6Al4V alloy substrates using dipping sol-gel method and electrophoresis. The selection of sol/suspension composition, deposition time and heat treatment conditions have the decisive influence on the layers parameters. The obtained layers should be very thin and almost amorphous. The specific nature of ceramic layers on the metal substrates excludes the use of some measurements methods or makes it difficult to interpret the measurement results. All the obtained samples were compared using XRD analysis data (GID technique), SEM with EDX measurements and FTIR spectroscopy (transmission and reflection techniques) before and after soaking in simulated body fluid. FTIR spectroscopy with mathematical treatment of the spectra (BIO-RAD Win-IR program, Arithmetic-subtract function) was used to detect the increase or decrease of any phosphate phases during SBF soaking. Based on the FTIR results the processes of hydroxyapatite (HAp) growth or layer dissolution were estimated. The layers deposited on titanium substrate are more crystalline then the ones deposited on Ti6Al4V. During SBF soaking process the growth of small amount of microcrystalline carbonate hydroxyapatite was observed on titanium substrate. The layer on Ti6Al4V base contained amorphous carbonate apatite. During heating treatment above about 870-920 K this apatite transforms into carbonate hydroxyapatite. The Ti6Al4V substrate seems to be more advantageous in context of potentially bioactive materials obtaining. Copyright © 2010 Elsevier B.V. All rights reserved.

The comparison of phosphate-titanate-silicate layers on the titanium and Ti6Al4V alloy base

NASA Astrophysics Data System (ADS)

Rokita, M.

2011-08-01

The studied layers were composed of two parts: titanate-silicate underlayer for better adhesion and titanate-phosphate-silicate layers for potential bioparameters. The layers with different amounts of hydroxyapatite were deposited on titanium and Ti6Al4V alloy substrates using dipping sol-gel method and electrophoresis. The selection of sol/suspension composition, deposition time and heat treatment conditions have the decisive influence on the layers parameters. The obtained layers should be very thin and almost amorphous. The specific nature of ceramic layers on the metal substrates excludes the use of some measurements methods or makes it difficult to interpret the measurement results. All the obtained samples were compared using XRD analysis data (GID technique), SEM with EDX measurements and FTIR spectroscopy (transmission and reflection techniques) before and after soaking in simulated body fluid. FTIR spectroscopy with mathematical treatment of the spectra (BIO-RAD Win-IR program, Arithmetic-subtract function) was used to detect the increase or decrease of any phosphate phases during SBF soaking. Based on the FTIR results the processes of hydroxyapatite (HAp) growth or layer dissolution were estimated. The layers deposited on titanium substrate are more crystalline then the ones deposited on Ti6Al4V. During SBF soaking process the growth of small amount of microcrystalline carbonate hydroxyapatite was observed on titanium substrate. The layer on Ti6Al4V base contained amorphous carbonate apatite. During heating treatment above about 870-920 K this apatite transforms into carbonate hydroxyapatite. The Ti6Al4V substrate seems to be more advantageous in context of potentially bioactive materials obtaining.

Electrochemical Deposition of Conformal and Functional Layers on High Aspect Ratio Silicon Micro/Nanowires.

PubMed

Ozel, Tuncay; Zhang, Benjamin A; Gao, Ruixuan; Day, Robert W; Lieber, Charles M; Nocera, Daniel G

2017-07-12

Development of new synthetic methods for the modification of nanostructures has accelerated materials design advances to furnish complex architectures. Structures based on one-dimensional (1D) silicon (Si) structures synthesized using top-down and bottom-up methods are especially prominent for diverse applications in chemistry, physics, and medicine. Yet further elaboration of these structures with distinct metal-based and polymeric materials, which could open up new opportunities, has been difficult. We present a general electrochemical method for the deposition of conformal layers of various materials onto high aspect ratio Si micro- and nanowire arrays. The electrochemical deposition of a library of coaxial layers comprising metals, metal oxides, and organic/inorganic semiconductors demonstrate the materials generality of the synthesis technique. Depositions may be performed on wire arrays with varying diameter (70 nm to 4 μm), pitch (5 μ to 15 μ), aspect ratio (4:1 to 75:1), shape (cylindrical, conical, hourglass), resistivity (0.001-0.01 to 1-10 ohm/cm 2 ), and substrate orientation. Anisotropic physical etching of wires with one or more coaxial shells yields 1D structures with exposed tips that can be further site-specifically modified by an electrochemical deposition approach. The electrochemical deposition methodology described herein features a wafer-scale synthesis platform for the preparation of multifunctional nanoscale devices based on a 1D Si substrate.

High efficiency, low cost, thin film silicon solar cell design and method for making

DOEpatents

Sopori, Bhushan L.

2001-01-01

A semiconductor device having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer.

High efficiency low cost thin film silicon solar cell design and method for making

DOEpatents

Sopori, Bhushan L.

1999-01-01

A semiconductor device having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer.

Chemical vapor deposition of sialon

DOEpatents

Landingham, Richard L.; Casey, Alton W.

1982-01-01

A laminated composite and a method for forming the composite by chemical vapor deposition. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200.degree. C.; and impinging a gas containing in a flowing atmosphere of air N.sub.2, SiCl.sub.4, and AlCl.sub.3 on the surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hannachi, Amira, E-mail: amira.hannachi88@gmail.com; Maghraoui-Meherzi, Hager

Manganese sulfide thin films have been deposited on glass slides by chemical bath deposition (CBD) method. The effects of preparative parameters such as deposition time, bath temperature, concentration of precursors, multi-layer deposition, different source of manganese, different complexing agent and thermal annealing on structural and morphological film properties have been investigated. The prepared thin films have been characterized using the X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). It exhibit the metastable forms of MnS, the hexagonal γ-MnS wurtzite phase with preferential orientation in the (002) plane or the cubic β-MnS zinc blende with preferentialmore » orientation in the (200) plane. Microstructural studies revealed the formation of MnS crystals with different morphologies, such as hexagons, spheres, cubes or flowers like. - Graphical Abstract: We report the preparation of different phases of manganese sulfide thin films (γ, β and α-MnS) by chemical bath deposition method. The effects of deposition parameters such as deposition time and temperature, concentrations of precursors and multi-layer deposition on MnS thin films structure and morphology were investigated. The influence of thermal annealing under nitrogen atmosphere at different temperature on MnS properties was also studied. Different manganese precursors as well as different complexing agent were also used. - Highlights: • γ and β-MnS films were deposited on substrate using the chemical bath deposition. • The effect of deposition parameters on MnS film properties has been investigated. • Multi-layer deposition was also studied to increase film thickness. • The effect of annealing under N{sub 2} at different temperature was investigated.« less

Soap-film coating: High-speed deposition of multilayer nanofilms

PubMed Central

Zhang, Renyun; Andersson, Henrik A.; Andersson, Mattias; Andres, Britta; Edlund, Håkan; Edström, Per; Edvardsson, Sverker; Forsberg, Sven; Hummelgård, Magnus; Johansson, Niklas; Karlsson, Kristoffer; Nilsson, Hans-Erik; Norgren, Magnus; Olsen, Martin; Uesaka, Tetsu; Öhlund, Thomas; Olin, Håkan

2013-01-01

The coating of thin films is applied in numerous fields and many methods are employed for the deposition of these films. Some coating techniques may deposit films at high speed; for example, ordinary printing paper is coated with micrometre-thick layers of clay at a speed of tens of meters per second. However, to coat nanometre thin films at high speed, vacuum techniques are typically required, which increases the complexity of the process. Here, we report a simple wet chemical method for the high-speed coating of films with thicknesses at the nanometre level. This soap-film coating technique is based on forcing a substrate through a soap film that contains nanomaterials. Molecules and nanomaterials can be deposited at a thickness ranging from less than a monolayer to several layers at speeds up to meters per second. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology. PMID:23503102

Method of deposition of silicon carbide layers on substrates

DOEpatents

Angelini, P.; DeVore, C.E.; Lackey, W.J.; Blanco, R.E.; Stinton, D.P.

1982-03-19

A method for direct chemical vapor deposition of silicon carbide to substrates, especially nuclear waste particles, is provided by the thermal decomposition of methylsilane at 800 to 1050/sup 0/C when the substrates have been confined within a suitable coating environment.

Dynamic mask for producing uniform or graded-thickness thin films

DOEpatents

Folta, James A [Livermore, CA

2006-06-13

A method for producing single layer or multilayer films with high thickness uniformity or thickness gradients. The method utilizes a moving mask which blocks some of the flux from a sputter target or evaporation source before it deposits on a substrate. The velocity and position of the mask is computer controlled to precisely tailor the film thickness distribution. The method is applicable to any type of vapor deposition system, but is particularly useful for ion beam sputter deposition and evaporation deposition; and enables a high degree of uniformity for ion beam deposition, even for near-normal incidence of deposition species, which may be critical for producing low-defect multilayer coatings, such as required for masks for extreme ultraviolet lithography (EUVL). The mask can have a variety of shapes, from a simple solid paddle shape to a larger mask with a shaped hole through which the flux passes. The motion of the mask can be linear or rotational, and the mask can be moved to make single or multiple passes in front of the substrate per layer, and can pass completely or partially across the substrate.

Method for high-precision multi-layered thin film deposition for deep and extreme ultraviolet mirrors

DOEpatents

Ruffner, J.A.

1999-06-15

A method for coating (flat or non-flat) optical substrates with high-reflectivity multi-layer coatings for use at Deep Ultra-Violet (DUV) and Extreme Ultra-Violet (EUV) wavelengths. The method results in a product with minimum feature sizes of less than 0.10 [micro]m for the shortest wavelength (13.4 nm). The present invention employs a computer-based modeling and deposition method to enable lateral and vertical thickness control by scanning the position of the substrate with respect to the sputter target during deposition. The thickness profile of the sputter targets is modeled before deposition and then an appropriate scanning algorithm is implemented to produce any desired, radially-symmetric thickness profile. The present invention offers the ability to predict and achieve a wide range of thickness profiles on flat or figured substrates, i.e., account for 1/R[sup 2] factor in a model, and the ability to predict and accommodate changes in deposition rate as a result of plasma geometry, i.e., over figured substrates. 15 figs.

Method for generating small and ultra small apertures, slits, nozzles and orifices

DOEpatents

Khounsary, Ali M [Hinsdale, IL

2012-05-22

A method and device for one or more small apertures, slits, nozzles and orifices, preferably having a high aspect ratio. In one embodiment, one or more alternating layers of sacrificial layers and blocking layers are deposited onto a substrate. Each sacrificial layer is made of a material which preferably allows a radiation to substantially pass through. Each blocking layer is made of a material which substantially blocks the radiation.

Solar cells based on electrodeposited thin films of ZnS, CdS, CdSSe and CdTe

NASA Astrophysics Data System (ADS)

Weerasinghe, Ajith R.

The motivations of this research were to produce increased efficiency and low-cost solar cells. The production efficiency of Si solar cells has almost reached their theoretical limit, and reducing the manufacturing cost of Si solar cells is difficult to achieve due to the high-energy usage in material purifying and processing stages. Due to the low usage of materials and input energy, thin film solar cells have the potential to reduce the costs. CdS/CdTe thin film solar cells are already the cheapest on $/W basis. The cost of CdTe solar cells can be further reduced if all the semiconducting layers are fabricated using the electrodeposition (ED) method. ED method is scalable, low in the usage of energy and raw materials. These benefits lead to the cost effective production of semiconductors. The conventional method of fabricating CdS layers produces Cd containing waste solutions routinely, which adds to the cost of solar cells.ZnS, CdS and CdS(i-X)Sex buffer and window layers and CdTe absorber layers have been successfully electrodeposited and explored under this research investigation. These layers were fully characterised using complementary techniques to evaluate the material properties. Photoelectrochemical (PEC) studies, optical absorption, X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, atomic force microscopy (AFM) and Raman spectroscopy were utilised to evaluate the material properties of these solid thin film layers. ZnS and CdS thin film layers were electrodeposited from Na-free chemical precursors to avoid the group I element (Na) to reduce deterioration of CdTe devices. Deposition parameters such as, growth substrates, temperature, pH, growth cathodic voltage, stirring rate, time and chemical concentrations were identified to fabricate the above semiconductors. To further optimise these layers, a heat treatment process specific to the material was developed. In addition, the deposition parameters of CdTe layers were further optimised. This research programme has demonstrated that electrodeposited ZnS, CdS and CdTe thin film layers have material characteristics comparable with those of the materials reported in the literature and can be used in thin film solar cell devices. Furthermore, the electrolytes were used for up to two years, reducing the wastage even further, in comparison to other fabrication methods, such as chemical bath deposition. Several large-area semiconducting layers were successfully fabricated to test the scalability of the method. Nano-rods perpendicular to the glass/FTO surface with gaps among grains in CdS layers were observed. In order to reduce the possible pinholes due the gaps, a deposition of a semiconducting layer to cover completely the substrate was investigated. CdS(i-X)Sex layers were investigated to produce a layer-by-layer deposition of the material. However it was observed the surface morphology of CdS(j.X)Sex is a function of the growth parameters which produced nano-wires, nano-tubes and nano-sheets. This is the first recording of this effect for a low temperature deposition method, minimising the cost of producing this highly photosensitive material for use in various nano technology applications.The basic structure experimented was glass/conducting-glass/buffer layer/window material/absorber material/metal. By utilising all the semiconducting layers developed, several solar cell device structures were designed, fabricated and tested. This included a novel all-electrodeposited multi-layer graded bandgap device, to enhance the absorption of solar photons. The device efficiencies varied from batch to batch, and efficiencies in the range (3-7)% were observed. The variations in chemical concentrations, surface states and the presence of pin-hole defects in CdS were the main reasons for the range of efficiencies obtained. In the future work section, ways to avoid these variations and to increase efficiencies are identified and presented.

Fabrication of microchannels in polycrystalline diamond using pre-fabricated Si substrates

NASA Astrophysics Data System (ADS)

Chandran, Maneesh; Elfimchev, Sergey; Michaelson, Shaul; Akhvlediani, Rozalia; Ternyak, Orna; Hoffman, Alon

2017-10-01

In this paper, we report on a simple, feasible method to fabricate microchannels in diamond. Polycrystalline diamond microchannels were produced by fabricating trenches in a Si wafer and subsequently depositing a thin layer of diamond onto this substrate using the hot filament vapor deposition technique. Fabrication of trenches in the Si substrate at different depths was carried out by standard photolithography, and the subsequent deposition of the diamond layer was performed by the hot filament chemical vapor deposition technique. The growth mechanism of diamond that leads to the formation of closed diamond microchannels is discussed in detail based on the Knudsen number and growth chemistry of diamond. Variations in the crystallite size, crystalline quality, and thickness of the diamond layer along the trench depths were systematically analyzed using cross-sectional scanning electron microscopy and Raman spectroscopy. Defect density and formation of non-diamond forms of carbon in the diamond layer were found to increase with the trench depth, which sets a limit of 5-45 μm trench depth (or an aspect ratio of 1-9) for the fabrication of diamond microchannels using this method under the present conditions.

Method for making circular tubular channels with two silicon wafers

DOEpatents

Yu, Conrad M.; Hui, Wing C.

1996-01-01

A two-wafer microcapillary structure is fabricated by depositing boron nitride (BN) or silicon nitride (Si.sub.3 N.sub.4) on two separate silicon wafers (e.g., crystal-plane silicon with [100] or [110] crystal orientation). Photolithography is used with a photoresist to create exposed areas in the deposition for plasma etching. A slit entry through to the silicon is created along the path desired for the ultimate microcapillary. Acetone is used to remove the photoresist. An isotropic etch, e.g., such as HF/HNO.sub.3 /CH.sub.3 COOH, then erodes away the silicon through the trench opening in the deposition layer. A channel with a half-circular cross section is then formed in the silicon along the line of the trench in the deposition layer. Wet etching is then used to remove the deposition layer. The two silicon wafers are aligned and then bonded together face-to-face to complete the microcapillary.

Acoustic resonator with Al electrodes on an AlN layer and using a GaAs substrate

DOEpatents

Kline, Gerald R.; Lakin, Kenneth M.

1985-12-03

A method of fabricating an acoustic wave resonator wherein all processing steps are accomplished from a single side of said substrate. The method involves deposition of a multi-layered Al/AlN structure on a GaAs substrate followed by a series of fabrication steps to define a resonator from said composite. The resulting resonator comprises an AlN layer between two Al layers and another layer of AlN on an exterior of one of said Al layers.

Some aspects over the quality of thin films deposited on special steels used in hydraulic blades

NASA Astrophysics Data System (ADS)

Tugui, C. A.; Vizureanu, P.; Iftimie, N.; Steigmann, R.

2016-08-01

The experimental research involved in this paper consists in the obtaining of superior physical, chemical and mechanical properties of stainless steels used in the construction of hydraulic turbine blades. These properties are obtained by deposition of hard thin films in order to improve the wear resistance, increasing the hardness but maintaining the tenacious core of the material. The chosen methods for deposition are electrospark deposition because it has relatively low costs, are easy to obtain, the layers have a good adherence to support and the thickness can be variable in function of the established conditions and the pulsed laser deposition because high quality films can be obtained at nanometric precision. The samples will be prepared for the analysis of the structure using optical method as well as for the obtaining of the optimal roughness for the deposition. The physical, chemical and mechanical properties will be determined after deposition using SEM and EDX, in order to emphasize the structure film-substrate and repartition of the deposition elements on the surface and in transversal section. The non-destructive testing has emphasized the good adherence between deposited layer and the metallic support, due to double deposition, spallation regions doesn't appear.

Post-mortem analysis on LiFePO4|Graphite cells describing the evolution & composition of covering layer on anode and their impact on cell performance

NASA Astrophysics Data System (ADS)

Lewerenz, Meinert; Warnecke, Alexander; Sauer, Dirk Uwe

2017-11-01

During cyclic aging of lithium-ion batteries the formation of a μm-thick covering layer on top of the anode facing the separator is found on top of the anode. In this work several post-mortem analyses of cyclic aged cylindrical LFP|Graphite cells are evaluated to give a detailed characterization of the covering layer and to find possible causes for the evolution of such a layer. The analyses of the layer with different methods return that it consists to high percentage of plated active lithium, deposited Fe and products of a solid electrolyte interphase (SEI). The deposition is located mainly in the center of the cell symmetrical to the coating direction. The origin of these depositions is assumed in locally overcharged particles, Fe deposition or inhomogeneous distribution of capacity density. As a secondary effect the deposition on one side increases the thickness locally; thereafter a pressure-induced overcharging due to charge agglomeration of the back side of the anode occurs. Finally a compact and dense covering layer in a late state of aging leads to deactivation of the covered parts of the anode and cathode due to suppressed lithium-ion conductivity. This leads to increasing slope of capacity fade and increase of internal resistance.

Method of producing solution-derived metal oxide thin films

DOEpatents

Boyle, Timothy J.; Ingersoll, David

2000-01-01

A method of preparing metal oxide thin films by a solution method. A .beta.-metal .beta.-diketonate or carboxylate compound, where the metal is selected from groups 8, 9, 10, 11, and 12 of the Periodic Table, is solubilized in a strong Lewis base to form a homogeneous solution. This precursor solution forms within minutes and can be deposited on a substrate in a single layer or a multiple layers to form a metal oxide thin film. The substrate with the deposited thin film is heated to change the film from an amorphous phase to a ceramic metal oxide and cooled.

Methods for using atomic layer deposition to produce a film for solid state electrolytes and protective electrode coatings for lithium batteries

DOEpatents

Elam, Jeffrey W.; Meng, Xiangbo

2018-03-13

A method for using atomic layer deposition to produce a film configured for use in an anode, cathode, or solid state electrolyte of a lithium-ion battery or a lithium-sulfur battery. The method includes repeating a cycle for a predetermined number of times in an inert atmosphere. The cycle includes exposing a substrate to a first precursor, purging the substrate with inert gas, exposing the substrate to a second precursor, and purging the substrate with inert gas. The film is a metal sulfide.

Lift-off process with bi-layer photoresist patterns for conformal-coated superhydrophilic pulsed plasma chemical vapor deposition-SiOx on SiCx for lab-on-a-chip applications

NASA Astrophysics Data System (ADS)

Konishi, Satoshi; Nakagami, Chise; Kobayashi, Taizo; Tonomura, Wataru; Kaizuma, Yoshihiro

2015-04-01

In this work, a lift-off process with bi-layer photoresist patterns was applied to the formation of hydrophobic/hydrophilic micropatterns on practical polymer substrates used in healthcare diagnostic commercial products. The bi-layer photoresist patterns with undercut structures made it possible to peel the conformal-coated silicon oxide (SiOx) films from substrates. SiOx and silicon carbide (SiCx) layers were deposited by pulsed plasma chemical vapor deposition (PPCVD) method which can form roughened surfaces to enhance hydrophilicity of SiOx and hydrophobicity of SiCx. Microfluidic applications using hydrophobic/hydrophilic patterns were also demonstrated on low-cost substrates such as poly(ethylene terephthalate) (PET) and paper films.

Metallic dielectric photonic crystals and methods of fabrication

DOEpatents

Chou, Jeffrey Brian; Kim, Sang-Gook

2017-12-05

A metallic-dielectric photonic crystal is formed with a periodic structure defining a plurality of resonant cavities to selectively absorb incident radiation. A metal layer is deposited on the inner surfaces of the resonant cavities and a dielectric material fills inside the resonant cavities. This photonic crystal can be used to selectively absorb broadband solar radiation and then reemit absorbed radiation in a wavelength band that matches the absorption band of a photovoltaic cell. The photonic crystal can be fabricated by patterning a sacrificial layer with a plurality of holes, into which is deposited a supporting material. Removing the rest of the sacrificial layer creates a supporting structure, on which a layer of metal is deposited to define resonant cavities. A dielectric material then fills the cavities to form the photonic crystal.

Analysis of signals propagating in a phononic crystal PZT layer deposited on a silicon substrate.

PubMed

Hladky-Hennion, Anne-Christine; Vasseur, Jérôme; Dubus, Bertrand; Morvan, Bruno; Wilkie-Chancellier, Nicolas; Martinez, Loïc

2013-12-01

The design of a stop-band filter constituted by a periodically patterned lead zirconate titanate (PZT) layer, polarized along its thickness, deposited on a silicon substrate and sandwiched between interdigitated electrodes for emission/reception of guided elastic waves, is investigated. The filter characteristics are theoretically evaluated by using finite element simulations: dispersion curves of a patterned PZT layer with a specific pattern geometry deposited on a silicon substrate present an absolute stop band. The whole structure is modeled with realistic conditions, including appropriate interdigitated electrodes to propagate a guided mode in the piezoelectric layer. A robust method for signal analysis based on the Gabor transform is applied to treat transmitted signals; extract attenuation, group delays, and wave number variations versus frequency; and identify stop-band filter characteristics.

SERS Taper-Fiber Nanoprobe Modified by Gold Nanoparticles Wrapped with Ultrathin Alumina Film by Atomic Layer Deposition

PubMed Central

Xu, Wenjie; Chen, Zhenyi; Chen, Na; Zhang, Heng; Liu, Shupeng; Hu, Xinmao; Wen, Jianxiang; Wang, Tingyun

2017-01-01

A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-assembly technology, and then the TFNP was wrapped with ultrathin alumina layers by the atomic layer deposition (ALD) technique. The results told us that with the increasing thickness of the alumina film, the Raman signals decreased. With approximately 1 nm alumina film, the remote detection limit for R6G aqueous solution reached 10−6 mol/L. PMID:28245618

Metallic dielectric photonic crystals and methods of fabrication

DOEpatents

Chou, Jeffrey Brian; Kim, Sang-Gook

2016-12-20

A metallic-dielectric photonic crystal is formed with a periodic structure defining a plurality of resonant cavities to selectively absorb incident radiation. A metal layer is deposited on the inner surfaces of the resonant cavities and a dielectric material fills inside the resonant cavities. This photonic crystal can be used to selectively absorb broadband solar radiation and then reemit absorbed radiation in a wavelength band that matches the absorption band of a photovoltaic cell. The photonic crystal can be fabricated by patterning a sacrificial layer with a plurality of holes, into which is deposited a supporting material. Removing the rest of the sacrificial layer creates a supporting structure, on which a layer of metal is deposited to define resonant cavities. A dielectric material then fills the cavities to form the photonic crystal.

Process for depositing Cr-bearing layer

DOEpatents

Ellis, Timothy W.; Lograsso, Thomas A.; Eshelman, Mark A.

1995-05-09

A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate.

Process for depositing Cr-bearing layer

DOEpatents

Ellis, T.W.; Lograsso, T.A.; Eshelman, M.A.

1995-05-09

A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate. 7 figs.

Emerging Applications for High K Materials in VLSI Technology

PubMed Central

Clark, Robert D.

2014-01-01

The current status of High K dielectrics in Very Large Scale Integrated circuit (VLSI) manufacturing for leading edge Dynamic Random Access Memory (DRAM) and Complementary Metal Oxide Semiconductor (CMOS) applications is summarized along with the deposition methods and general equipment types employed. Emerging applications for High K dielectrics in future CMOS are described as well for implementations in 10 nm and beyond nodes. Additional emerging applications for High K dielectrics include Resistive RAM memories, Metal-Insulator-Metal (MIM) diodes, Ferroelectric logic and memory devices, and as mask layers for patterning. Atomic Layer Deposition (ALD) is a common and proven deposition method for all of the applications discussed for use in future VLSI manufacturing. PMID:28788599

A new approach to the deposition of nanostructured biocatalytic films

NASA Astrophysics Data System (ADS)

Troitsky, V. I.; Berzina, T. S.; Pastorino, L.; Bernasconi, E.; Nicolini, C.

2003-06-01

In the present work, monolayer engineering was used to fabricate biocatalytic nanostructured thin films based on the enzyme penicillin G acylase. The biocatalytic films with enhanced characteristics were produced by the deposition of alternate-layer assemblies with a predetermined structure using a combination of Langmuir-Blodgett and adsorption techniques. The value of enzyme activity and the level of protein detachment were measured in dependence on the variation of film composition and on the sequence of layer alternation. As a result, highly active and stable structures were found, which could be promising candidates for practical applications. The method of modification of the deposition method to provide continuous film formation on large-area supports is discussed.

Compliant layer chucking surface

DOEpatents

Blaedel, Kenneth L [Dublin, CA; Spence, Paul A [Pleasanton, CA; Thompson, Samuel L [Pleasanton, CA

2004-12-28

A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

Method of forming an HTS article

DOEpatents

Bhattacharya, Raghu N.; Zhang, Xun; Selvamanickam, Venkat

2014-08-19

A method of forming a superconducting article includes providing a substrate tape, forming a superconducting layer overlying the substrate tape, and depositing a capping layer overlying the superconducting layer. The capping layer includes a noble metal and has a thickness not greater than about 1.0 micron. The method further includes electrodepositing a stabilizer layer overlying the capping layer using a solution that is non-reactive to the superconducting layer. The superconducting layer has an as-formed critical current I.sub.C(AF) and a post-stabilized critical current I.sub.C(PS). The I.sub.C(PS) is at least about 95% of the I.sub.C(AF).

Fabrication of nano-gap electrode arrays by the construction and selective chemical etching of nano-crosswire stacks

NASA Technical Reports Server (NTRS)

Prokopuk, Nicholas (Inventor); Son, Kyung-Ah (Inventor)

2008-01-01

Methods of fabricating nano-gap electrode structures in array configurations, and the structures so produced. The fabrication method involves depositing first and second pluralities of electrodes comprising nanowires using processes such as lithography, deposition of metals, lift-off processes, and chemical etching that can be performed using conventional processing tools applicable to electronic materials processing. The gap spacing in the nano-gap electrode array is defined by the thickness of a sacrificial spacer layer that is deposited between the first and second pluralities of electrodes. The sacrificial spacer layer is removed by etching, thereby leaving a structure in which the distance between pairs of electrodes is substantially equal to the thickness of the sacrificial spacer layer. Electrode arrays with gaps measured in units of nanometers are produced. In one embodiment, the first and second pluralities of electrodes are aligned in mutually orthogonal orientations.

Method of making an icosahedral boride structure

DOEpatents

Hersee, Stephen D.; Wang, Ronghua; Zubia, David; Aselage, Terrance L.; Emin, David

2005-01-11

A method for fabricating thin films of an icosahedral boride on a silicon carbide (SiC) substrate is provided. Preferably the icosahedral boride layer is comprised of either boron phosphide (B.sub.12 P.sub.2) or boron arsenide (B.sub.12 As.sub.2). The provided method achieves improved film crystallinity and lowered impurity concentrations. In one aspect, an epitaxially grown layer of B.sub.12 P.sub.2 with a base layer or substrate of SiC is provided. In another aspect, an epitaxially grown layer of B.sub.12 As.sub.2 with a base layer or substrate of SiC is provided. In yet another aspect, thin films of B.sub.12 P.sub.2 or B.sub.12 As.sub.2 are formed on SiC using CVD or other vapor deposition means. If CVD techniques are employed, preferably the deposition temperature is above 1050.degree. C., more preferably in the range of 1100.degree. C. to 1400.degree. C., and still more preferably approximately 1150.degree. C.

Changing the thickness of two layers: i-ZnO nanorods, p-Cu2O and its influence on the carriers transport mechanism of the p-Cu2O/i-ZnO nanorods/n-IGZO heterojunction.

PubMed

Ke, Nguyen Huu; Trinh, Le Thi Tuyet; Phung, Pham Kim; Loan, Phan Thi Kieu; Tuan, Dao Anh; Truong, Nguyen Huu; Tran, Cao Vinh; Hung, Le Vu Tuan

2016-01-01

In this study, two layers: i-ZnO nanorods and p-Cu2O were fabricated by electrochemical deposition. The fabricating process was the initial formation of ZnO nanorods layer on the n-IGZO thin film which was prepared by sputtering method, then a p-Cu2O layer was deposited on top of rods to form the p-Cu2O/i-ZnO nanorods/n-ZnO heterojunction. The XRD, SEM, UV-VIS, I-V characteristics methods were used to define structure, optical and electrical properties of these heterojunction layers. The fabricating conditions and thickness of the Cu2O layers significantly affected to the formation, microstructure, electrical and optical properties of the junction. The length of i-ZnO nanorods layer in the structure of the heterojunction has strongly affected to the carriers transport mechanism and performance of this heterojunction.

Optimization of hetero-epitaxial growth for the threading dislocation density reduction of germanium epilayers

NASA Astrophysics Data System (ADS)

Chong, Haining; Wang, Zhewei; Chen, Chaonan; Xu, Zemin; Wu, Ke; Wu, Lan; Xu, Bo; Ye, Hui

2018-04-01

In order to suppress dislocation generation, we develop a "three-step growth" method to heteroepitaxy low dislocation density germanium (Ge) layers on silicon with the MBE process. The method is composed of 3 growth steps: low temperature (LT) seed layer, LT-HT intermediate layer as well as high temperature (HT) epilayer, successively. Threading dislocation density (TDD) of epitaxial Ge layers is measured as low as 1.4 × 106 cm-2 by optimizing the growth parameters. The results of Raman spectrum showed that the internal strain of heteroepitaxial Ge layers is tensile and homogeneous. During the growth of LT-HT intermediate layer, TDD reduction can be obtained by lowering the temperature ramping rate, and high rate deposition maintains smooth surface morphology in Ge epilayer. A mechanism based on thermodynamics is used to explain the TDD and surface morphological dependence on temperature ramping rate and deposition rate. Furthermore, we demonstrate that the Ge layer obtained can provide an excellent platform for III-V materials integrated on Si.

Single layer multi-color luminescent display and method of making

NASA Technical Reports Server (NTRS)

Robertson, James B. (Inventor)

1992-01-01

The invention is a multi-color luminescent display comprising an insulator substrate and a single layer of host material, which may be a phosphor deposited thereon that hosts one or more different impurities, therein forming a pattern of selected and distinctly colored phosphors such as blue, green, and red phosphors in a single layer of host material. Transparent electrical conductor means may be provided for subjecting selected portions of the pattern of colored phosphors to an electric field, thereby forming a multi-color, single layer electroluminescent display. A method of forming a multi-color luminescent display includes the steps of depositing on an insulator substrate a single layer of host material, which itself may be a phosphor, with the properties to host varying quantities of different impurities and introducing one or more of said different impurities into selected areas of the said single layer of host material by thermal diffusion or ion implantation to form a pattern of phosphors of different colors in the said single layer of host material.

Method for deposition of a conductor in integrated circuits

DOEpatents

Creighton, J.R.; Dominguez, F.; Johnson, A.W.; Omstead, T.R.

1997-09-02

A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten. 2 figs.

Method of deposition of silicon carbide layers on substrates and product

DOEpatents

Angelini, Peter; DeVore, Charles E.; Lackey, Walter J.; Blanco, Raymond E.; Stinton, David P.

1984-01-01

A method for direct chemical vapor deposition of silicon carbide to substrates, especially nuclear waste particles, is provided by the thermal decomposition of methylsilane at about 800.degree. C. to 1050.degree. C. when the substrates have been confined within a suitable coating environment.

Experimental studies of thin films deposition by magnetron sputtering method for CIGS solar cell fabrication

NASA Astrophysics Data System (ADS)

Gułkowski, Sławomir; Krawczak, Ewelina

2017-10-01

Among a variety of the thin film solar cell technologies of second generation, copper-indium-gallium-diselenide device (CIGS) with the latest highest lab cell efficiency record of 22.4 % seems to be the most promising for the power generation. This is partly due to the advantages of using low cost films of few microns thick not only as a metallic contacts but also as a main structure of the solar cell consisted of high quality semiconductor layers. This paper reports the experimental studies of the CIGS absorber formation on Soda Lime Glass substrate covered by thin molybdenum film as a back contact layer. All structures were deposited with the use of magnetron sputtering method only. Technological parameters of the deposition process such as deposition power, pressure and deposition time were optimized for each layer of the structure. Mo back contact was examined in terms of resistivity. EDS measurements were carried out to verify stoichiometric composition of CIGS absorber. Thin film of Al was used as a top contact in order to examine the quality of p-n junction. The I-V electrical characteristic of the p-n junction was analysed in terms of solar cell application.

Large-scale Growth and Simultaneous Doping of Molybdenum Disulfide Nanosheets

PubMed Central

Kim, Seong Jun; Kang, Min-A; Kim, Sung Ho; Lee, Youngbum; Song, Wooseok; Myung, Sung; Lee, Sun Sook; Lim, Jongsun; An, Ki-Seok

2016-01-01

A facile method that uses chemical vapor deposition (CVD) for the simultaneous growth and doping of large-scale molybdenum disulfide (MoS2) nanosheets was developed. We employed metalloporphyrin as a seeding promoter layer for the uniform growth of MoS2 nanosheets. Here, a hybrid deposition system that combines thermal evaporation and atomic layer deposition (ALD) was utilized to prepare the promoter. The doping effect of the promoter was verified by X-ray photoelectron spectroscopy and Raman spectroscopy. In addition, the carrier density of the MoS2 nanosheets was manipulated by adjusting the thickness of the metalloporphyrin promoter layers, which allowed the electrical conductivity in MoS2 to be manipulated. PMID:27044862

Electrostatic force assisted deposition of graphene

DOEpatents

Liang, Xiaogan [Berkeley, CA

2011-11-15

An embodiment of a method of depositing graphene includes bringing a stamp into contact with a substrate over a contact area. The stamp has at least a few layers of the graphene covering the contact area. An electric field is developed over the contact area. The stamp is removed from the vicinity of the substrate which leaves at least a layer of the graphene substantially covering the contact area.

High efficiency low cost thin film silicon solar cell design and method for making

DOEpatents

Sopori, B.L.

1999-04-27

A semiconductor device is described having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer. 9 figs.

EDITORIAL: Atomic layer deposition Atomic layer deposition

NASA Astrophysics Data System (ADS)

Godlewski, Marek

2012-07-01

The growth method of atomic layer deposition (ALD) was introduced in Finland by Suntola under the name of atomic layer epitaxy (ALE). The method was originally used for deposition of thin films of sulphides (ZnS, CaS, SrS) activated with manganese or rare-earth ions. Such films were grown for applications in thin-film electroluminescence (TFEL) displays. The ALE mode of growth was also tested in the case of molecular beam epitaxy. Films grown by ALD are commonly polycrystalline or even amorphous. Thus, the name ALE has been replaced by ALD. In the 80s ALD was developed mostly in Finland and neighboring Baltic countries. Deposition of a range of different materials was demonstrated at that time, including II-VI semiconductors (e.g. CdTe, CdS) and III-V (e.g. GaAs, GaN), with possible applications in e.g. photovoltaics. The number of publications on ALD was slowly increasing, approaching about 100 each year. A real boom in interest came with the development of deposition methods of thin films of high-k dielectrics. This research was motivated by a high leakage current in field-effect transistors with SiO2-based gate dielectrics. In 2007 Intel introduced a new generation of integrated circuits (ICs) with thin films of HfO2 used as gate isolating layers. In these and subsequent ICs, films of HfO2 are deposited by the ALD method. This is due to their unique properties. The introduction of ALD to the electronics industry led to a booming interest in the ALD growth method, with the number of publications increasing rapidly to well above 1000 each year. A number of new applications were proposed, as reflected in this special issue of Semiconductor Science and Technology. The included articles cover a wide range of possible applications—in microelectronics, transparent electronics, optoelectronics, photovoltaics and spintronics. Research papers and reviews on the basics of ALD growth are also included, reflecting a growing interest in precursor chemistry and growth processes. Summarizing, this special issue of Semiconductor Science and Technology reflects the rapidly growing interest in the ALD growth method and demonstrates the wide range of possible practical applications of ALD-grown materials, not only of high-k dielectrics, but also of a range of different materials (e.g. ZnO). Finally, I would like to thank the IOP editorial staff, in particular Alice Malhador, for their support and efforts in making this special issue possible.

Investigation on structural and optical properties of ZnO film prepared by simple wet chemical method

NASA Astrophysics Data System (ADS)

Sholehah, Amalia; Mulyadi, Rendi; Haryono, Didied; Muttakin, Imamul; Rusbana, Tb Bahtiar; Mardiyanto

2018-04-01

ZnO thin layer has a broad potential application in electronic and optoelectronic devices. In this study, vertically align ZnO layers were deposited on ITO glass using wet chemistry method. The seed layers were prepared using electrodeposition technique at 3°C. The growing process was carried out using chemical bath deposition at 90°C. To improve the structural properties, two different hydrothermal treatment variations were applied separately. From the experiment, it is shown that the hydrothermal process using N2 gas has given the best result, with average diameter, crystallite size, and band-gap energy of 68.83 nm; 56.37 nm; and 3.16 eV, respectively.

Thin Film Catalyst Layers for Direct Methanol Fuel Cells

NASA Technical Reports Server (NTRS)

Witham, C. K.; Chun, W.; Ruiz, R.; Valdez, T. I.; Narayanan, S. R.

2000-01-01

One of the primary obstacles to the widespread use of the direct methanol fuel cell (DMFC) is the high cost of the catalyst. Therefore, reducing the catalyst loading well below the current level of 8-12 mg/cm 2 would be important to commercialization. The current methods for preparation of catalyst layers consisting of catalyst, ionomer and sometimes a hydrophobic additive are applied by either painting, spraying, decal transfer or screen printing processes. Sputter deposition is a coating technique widely used in manufacturing and therefore particularly attractive. In this study we have begun to explore sputtering as a method for catalyst deposition. Present experiments focus on Pt-Ru catalyst layers for the anode.

Method of fabricating reflection-mode EUV diffusers

DOEpatents

Anderson, Erik; Naulleau, Patrick P.

2005-03-01

Techniques for fabricating well-controlled, random relief, engineered surfaces that serve as substrates for EUV optical devices are accomplished with grayscale exposure. The method of fabricating a multilevel EUV optical element includes: (a) providing a substrate; (b) depositing a layer of curable material on a surface of the substrate; (c) creating a relief profile in a layer of cured material from the layer of curable material wherein the relief profile comprises multiple levels of cured material that has a defined contour; and (d) depositing a multilayer reflection film over the relief profile wherein the film has an outer contour that substantially matches that of the relief profile. The curable material can comprise photoresist or a low dielectric constant material.

Method of making dense, conformal, ultra-thin cap layers for nanoporous low-k ILD by plasma assisted atomic layer deposition

DOEpatents

Jiang, Ying-Bing [Albuquerque, NM; Cecchi, Joseph L [Albuquerque, NM; Brinker, C Jeffrey [Albuquerque, NM

2011-05-24

Barrier layers and methods for forming barrier layers on a porous layer are provided. The methods can include chemically adsorbing a plurality of first molecules on a surface of the porous layer in a chamber and forming a first layer of the first molecules on the surface of the porous layer. A plasma can then be used to react a plurality of second molecules with the first layer of first molecules to form a first layer of a barrier layer. The barrier layers can seal the pores of the porous material, function as a diffusion barrier, be conformal, and/or have a negligible impact on the overall ILD k value of the porous material.

Atomic layer deposition of quaternary chalcogenides

DOEpatents

Thimsen, Elijah J; Riha, Shannon C; Martinson, Alex B.F.; Elam, Jeffrey W; Pellin, Michael J

2014-06-03

Methods and systems are provided for synthesis and deposition of chalcogenides (including Cu.sub.2ZnSnS.sub.4). Binary compounds, such as metal sulfides, can be deposited by alternating exposures of the substrate to a metal cation precursor and a chalcogen anion precursor with purge steps between.

Buffer layers on biaxially textured metal substrates

DOEpatents

Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

2001-01-01

A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

Method for rubblizing an oil shale deposit for in situ retorting

DOEpatents

Lewis, Arthur E.

1977-01-01

A method for rubblizing an oil shale deposit that has been formed in alternate horizontal layers of rich and lean shale, including the steps of driving a horizontal tunnel along the lower edge of a rich shale layer of the deposit, sublevel caving by fan drilling and blasting of both rich and lean overlying shale layers at the distal end of the tunnel to rubblize the layers, removing a substantial amount of the accessible rubblized rich shale to permit the overlying rubblized lean shale to drop to tunnel floor level to form a column of lean shale, performing additional sublevel caving of rich and lean shale towards the proximate end of the tunnel, removal of a substantial amount of the additionally rubblized rich shale to allow the overlying rubblized lean shale to drop to tunnel floor level to form another column of rubblized lean shale, similarly performing additional steps of sublevel caving and removal of rich rubble to form additional columns of lean shale rubble in the rich shale rubble in the tunnel, and driving additional horizontal tunnels in the deposit and similarly rubblizing the overlying layers of rich and lean shale and forming columns of rubblized lean shale in the rich, thereby forming an in situ oil shale retort having zones of lean shale that remain permeable to hot retorting fluids in the presence of high rubble pile pressures and high retorting temperatures.

Methods of producing armor systems, and armor systems produced using such methods

DOEpatents

Chu, Henry S; Lillo, Thomas M; McHugh, Kevin M

2013-02-19

An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

Alkali metal for ultraviolet band-pass filter

NASA Technical Reports Server (NTRS)

Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

1993-01-01

An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

Method to control artifacts of microstructural fabrication

DOEpatents

Shul, Randy J.; Willison, Christi G.; Schubert, W. Kent; Manginell, Ronald P.; Mitchell, Mary-Anne; Galambos, Paul C.

2006-09-12

New methods for fabrication of silicon microstructures have been developed. In these methods, an etching delay layer is deposited and patterned so as to provide differential control on the depth of features being etched into a substrate material. Compensation for etching-related structural artifacts can be accomplished by proper use of such an etching delay layer.

Laser Synthesis of Supported Catalysts for Carbon Nanotubes

NASA Technical Reports Server (NTRS)

VanderWal, Randall L.; Ticich, Thomas M.; Sherry, Leif J.; Hall, Lee J.; Schubert, Kathy (Technical Monitor)

2003-01-01

Four methods of laser assisted catalyst generation for carbon nanotube (CNT) synthesis have been tested. These include pulsed laser transfer (PLT), photolytic deposition (PLD), photothermal deposition (PTD) and laser ablation deposition (LABD). Results from each method are compared based on CNT yield, morphology and structure. Under the conditions tested, the PLT was the easiest method to implement, required the least time and also yielded the best pattemation. The photolytic and photothermal methods required organometallics, extended processing time and partial vacuums. The latter two requirements also held for the ablation deposition approach. In addition to control of the substrate position, controlled deposition duration was necessary to achieve an active catalyst layer. Although all methods were tested on both metal and quartz substrates, only the quartz substrates proved to be inactive towards the deposited catalyst particles.

Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

PubMed

Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

2016-05-01

Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere.

Air-stable ink for scalable, high-throughput layer deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weil, Benjamin D; Connor, Stephen T; Cui, Yi

A method for producing and depositing air-stable, easily decomposable, vulcanized ink on any of a wide range of substrates is disclosed. The ink enables high-volume production of optoelectronic and/or electronic devices using scalable production methods, such as roll-to-roll transfer, fast rolling processes, and the like.

Controlled Synthesis of Pd/Pt Core Shell Nanoparticles Using Area-selective Atomic Layer Deposition

PubMed Central

Cao, Kun; Zhu, Qianqian; Shan, Bin; Chen, Rong

2015-01-01

We report an atomic scale controllable synthesis of Pd/Pt core shell nanoparticles (NPs) via area-selective atomic layer deposition (ALD) on a modified surface. The method involves utilizing octadecyltrichlorosilane (ODTS) self-assembled monolayers (SAMs) to modify the surface. Take the usage of pinholes on SAMs as active sites for the initial core nucleation, and subsequent selective deposition of the second metal as the shell layer. Since new nucleation sites can be effectively blocked by surface ODTS SAMs in the second deposition stage, we demonstrate the successful growth of Pd/Pt and Pt/Pd NPs with uniform core shell structures and narrow size distribution. The size, shell thickness and composition of the NPs can be controlled precisely by varying the ALD cycles. Such core shell structures can be realized by using regular ALD recipes without special adjustment. This SAMs assisted area-selective ALD method of core shell structure fabrication greatly expands the applicability of ALD in fabricating novel structures and can be readily applied to the growth of NPs with other compositions. PMID:25683469

Engineering the Mechanical Properties of Ultrabarrier Films Grown by Atomic Layer Deposition for the Encapsulation of Printed Electronics

DOE PAGES

Bulusu, Anuradha; Singh, Ankit K.; Wang, Cheng-Yin; ...

2015-08-28

Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion (CTE) mismatch, elastic mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition.more » We present the impact of architecture on the performance of aluminum oxide (Al2O3)/hafnium oxide (HfO2) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50{degree sign}C/85% RH. Inserting a SiNx layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers.« less

Process for Fabrication of Superconducting Vias for Electrical Connection to Groundplane in Cryogenic Detectors

NASA Technical Reports Server (NTRS)

Denis, Kevin L. (Inventor)

2018-01-01

Disclosed are systems, methods, and non-transitory computer-readable storage media for fabrication of silicon on insulator (SOI) wafers with a superconductive via for electrical connection to a groundplane. Fabrication of the SOI wafer with a superconductive via can involve depositing a superconducting groundplane onto a substrate with the superconducting groundplane having an oxidizing layer and a non-oxidizing layer. A layer of monocrystalline silicon can be bonded to the superconducting groundplane and a photoresist layer can be applied to the layer of monocrystalline silicon and the SOI wafer can be etched with the oxygen rich etching plasma, resulting in a monocrystalline silicon top layer with a via that exposes the superconducting groundplane. Then, the fabrication can involve depositing a superconducting surface layer to cover the via.

Nano-Al{sub 2}O{sub 3} multilayer film deposition on cotton fabrics by layer-by-layer deposition method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ugur, Sule S., E-mail: sule@mmf.sdu.edu.tr; Sariisik, Merih; Aktas, A. Hakan

Highlights: {yields} Cationic charges were created on the cotton fibre surfaces with 2,3-epoxypropyltrimethylammonium chloride. {yields} Al{sub 2}O{sub 3} nanoparticles were deposited on the cotton fabrics by layer-by-layer deposition. {yields} The fabrics deposited with the Al{sub 2}O{sub 3} nanoparticles exhibit better UV-protection and significant flame retardancy properties. {yields} The mechanical properties were improved after surface film deposition. -- Abstract: Al{sub 2}O{sub 3} nanoparticles were used for fabrication of multilayer nanocomposite film deposition on cationic cotton fabrics by electrostatic self-assembly to improve the mechanical, UV-protection and flame retardancy properties of cotton fabrics. Cotton fabric surface was modified with a chemical reaction tomore » build-up cationic charge known as cationization. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy were used to verify the presence of deposited nanolayers. Air permeability, whiteness value, tensile strength, UV-transmittance and Limited Oxygen Index properties of cotton fabrics were analyzed before and after the treatment of Al{sub 2}O{sub 3} nanoparticles by electrostatic self-assemblies. It was proved that the flame retardancy, tensile strength and UV-transmittance of cotton fabrics can be improved by Al{sub 2}O{sub 3} nanoparticle additive through electrostatic self-assembly process.« less

Pulse electro-deposition of copper on molybdenum for Cu(In,Ga)Se2 and Cu2ZnSnSe4 solar cell applications

NASA Astrophysics Data System (ADS)

Bi, Jinlian; Yao, Liyong; Ao, Jianping; Gao, Shoushuai; Sun, Guozhong; He, Qing; Zhou, Zhiqiang; Sun, Yun; Zhang, Yi

2016-09-01

The issues of rough surface morphology and the incorporated additives of the electro-deposited Cu layers, which exists in electrodeposition-based processes, is one of the major obstacles to improve the efficiency of Cu(In,Ga)Se2 (CIGSe) and Cu2ZnSnSe4 (CZTSe) solar cells. In this study, the pulse current electro-deposition method is employed to deposit smooth Cu film on Mo substrate in CuSO4 solution without any additives. Grain size of the deposited Cu film is decreased by high cathode polarization successfully. And the concentration polarization, which results from high pulse current density, is controlled successfully by adjusting the pulse frequency. Flat Cu film with smooth surface and compact structure is deposited as pulse current density @ 62.5 mA cm-2, pulse frequency @100,000 Hz, and duty cycle @ 25%. CIGSe and CZTSe absorber films with flat surface and uniform elemental distribution are prepared by selenizing the stacking metal layers electro-deposited by pulse current method. Finally, the CIGSe and CZTSe solar cells with conversion efficiency of 10.39% and 7.83% respectively are fabricated based on the smooth Cu films, which are better than the solar cells fabricated by the rough Cu film deposited by direct current electro-deposition method.

Effect of the Parameters of Gas-Powder Laser Surfacing on the Structural Characteristics of Reconditioned Surface Layer of Corrosion-Resistant Steels

NASA Astrophysics Data System (ADS)

Krylova, S. E.; Oplesnin, S. P.; Manakov, N. A.; Yasakov, A. S.; Strizhov, A. O.

2018-01-01

Results of the developed commercial process for reconditioning the surface of corrosion-resistant steels by the method of laser surfacing are presented. A comparative analysis of the microstructures of the deposited wear-resistant layer, of the zone of fusion with the matrix material and of the diffusion zone after different variants of surfacing is performed. The hardness of the deposited layer is measured and a nondestructive inspection of the latter for the presence of flaws is performed.

Ultrasound assisted deposition of silica coatings on titanium

NASA Astrophysics Data System (ADS)

Kaş, Recep; Ertaş, Fatma Sinem; Birer, Özgür

2012-10-01

We present a novel ultrasound assisted method for silica coating of titanium surfaces. The coatings are formed by “smashing” silica nanoparticles onto activated titanium surface in solution using intense ultrasonic field. Homogeneous silica coatings are formed by deposition of dense multiple layers of silica nanoparticles. Since the nanoparticles also grow during the reaction, the layers of the coatings have smaller particles on the substrate and larger particles towards the surface. The thickness of the coatings can be controlled with several experimental parameters. Silica layers with thickness over 200 nm are readily obtained.

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

PubMed Central

Sundberg, Pia

2014-01-01

Summary The possibility to deposit purely organic and hybrid inorganic–organic materials in a way parallel to the state-of-the-art gas-phase deposition method of inorganic thin films, i.e., atomic layer deposition (ALD), is currently experiencing a strongly growing interest. Like ALD in case of the inorganics, the emerging molecular layer deposition (MLD) technique for organic constituents can be employed to fabricate high-quality thin films and coatings with thickness and composition control on the molecular scale, even on complex three-dimensional structures. Moreover, by combining the two techniques, ALD and MLD, fundamentally new types of inorganic–organic hybrid materials can be produced. In this review article, we first describe the basic concepts regarding the MLD and ALD/MLD processes, followed by a comprehensive review of the various precursors and precursor pairs so far employed in these processes. Finally, we discuss the first proof-of-concept experiments in which the newly developed MLD and ALD/MLD processes are exploited to fabricate novel multilayer and nanostructure architectures by combining different inorganic, organic and hybrid material layers into on-demand designed mixtures, superlattices and nanolaminates, and employing new innovative nanotemplates or post-deposition treatments to, e.g., selectively decompose parts of the structure. Such layer-engineered and/or nanostructured hybrid materials with exciting combinations of functional properties hold great promise for high-end technological applications. PMID:25161845

Multi-material poly(lactic acid) scaffold fabricated via fused deposition modeling and direct hydroxyapatite injection as spacers in laminoplasty

NASA Astrophysics Data System (ADS)

Syuhada, Ghifari; Ramahdita, Ghiska; Rahyussalim, A. J.; Whulanza, Yudan

2018-02-01

Nowadays, additive manufacturing method has been used extensively to realize any product with specific attributes rather than the conventional subtractive manufacturing method. For instance, the additive manufacturing has enable us to construct a product layer-by-layer by successively depositing several materials in one session and one platform. This paper studied the properties of a 3D printed scaffold fabricated through Poly(Lactic-acid) (PLA) deposition modelling in combination with injectable hydroxyapatite (HA)/alginate as cell carrier. The scaffold was designed to serve as a spacer in cervical laminoplasty. Therefore, a series of test were conducted to elaborate the mechanical property, porosity and in-vitro toxicity testing. The results showed that the method is reliable to fabricate the scaffold as desired although the toxicity test needs more confirmation.

Influence of Carrier Gas Composition on the Stress of Al₂O₃ Coatings Prepared by the Aerosol Deposition Method.

PubMed

Schubert, Michael; Exner, Jörg; Moos, Ralf

2014-08-05

Al₂O₃ films were prepared by the aerosol deposition method at room temperature using different carrier gas compositions. The layers were deposited on alumina substrates and the film stress of the layer was calculated by measuring the deformation of the substrate. It was shown that the film stress can be halved by using oxygen instead of nitrogen or helium as the carrier gas. The substrates were annealed at different temperature steps to gain information about the temperature dependence of the reduction of the implemented stress. Total relaxation of the stress can already be achieved at 300 °C. The XRD pattern shows crystallite growth and reduction of microstrain while annealing.

Growth of biaxially textured template layers using ion beam assisted deposition

NASA Astrophysics Data System (ADS)

Park, Seh-Jin

A two-step IBAD (ion beam assisted deposition) method is investigated, and compared to the conventional IBAD methods. The two step method uses surface energy anisotropy to achieve uniaxial texture and ion beam irradiation for biaxial texture. The biaxial texture was achieved by selective surface etching and enhanced by grain overgrowth. In this method, biaxial texture alignment is performed on a (001) uniaxially textured buffer layer. The material selected for achieving uniaxial texture, YBCO (YBa2Cu3O7-x), has strong surface energy anisotropy. YBCO is chemically susceptible to the reaction with the adjacent layer. Yttria stabilized zirconia (YSZ) was used to prevent the reaction between YBCO and the substrates (polycrystalline Ni alloy [Hastelloy] and amorphous SiNx/Si). A SrTiO3 layer was deposited on the uniaxially textured YBCO layer to retard stoichiometry change with subsequent processing. STO is well lattice matched with YBCO. A top layer of Ni was then deposited. The Ni layer was used for studying the effect of grain overgrowth. The obtained uniaxial Ni films were used for subsequent ion beam processing. Ar ion beam irradiation onto the uniaxially textured Ni film was used to study the effect of selective grain etching in achieving in-plane aligned Ni grains. Additional Ni deposition induces the overgrowth of the in-plane aligned Ni grains and, finally, the overall in-plane alignment. The in-plane alignment is examined with XRD phi scan. The effect of surface polarity of insulating oxide substrates on the epitaxial growth behavior was investigated. The lattice strain energy was the most important factor for determining the orientation of Ni films on a non-polar surface. However, for a polar surface, the surface energy plays an important role in determining the final orientation of the Ni films based on the experimental and theoretical results. Y2O3 growth behavior was also studied. The lattice strain energy is the most important factor for Y2O3 growth on single crystalline substrates. The surface energy anisotropy is the most important factor for the growth on amorphous substrates. The XRD phi scan study shows that Ar ion beam irradiation with favorable angle of incidence enhances the in-plane alignment of Y2O3 films grown on randomly oriented substrates due to the ion channeling.

Lattice-mismatched GaInP LED devices and methods of fabricating same

DOEpatents

Mascarenhas, Angelo; Steiner, Myles A; Bhusal, Lekhnath; Zhang, Yong

2014-10-21

A method (100) of fabricating an LED or the active regions of an LED and an LED (200). The method includes growing, depositing or otherwise providing a bottom cladding layer (208) of a selected semiconductor alloy with an adjusted bandgap provided by intentionally disordering the structure of the cladding layer (208). A first active layer (202) may be grown above the bottom cladding layer (208) wherein the first active layer (202) is fabricated of the same semiconductor alloy, with however, a partially ordered structure. The first active layer (202) will also be fabricated to include a selected n or p type doping. The method further includes growing a second active layer (204) above the first active layer (202) where the second active layer (204) Is fabricated from the same semiconductor alloy.

Efficient Planar Perovskite Solar Cells Using Passivated Tin Oxide as an Electron Transport Layer.

PubMed

Lee, Yonghui; Lee, Seunghwan; Seo, Gabseok; Paek, Sanghyun; Cho, Kyung Taek; Huckaba, Aron J; Calizzi, Marco; Choi, Dong-Won; Park, Jin-Seong; Lee, Dongwook; Lee, Hyo Joong; Asiri, Abdullah M; Nazeeruddin, Mohammad Khaja

2018-06-01

Planar perovskite solar cells using low-temperature atomic layer deposition (ALD) of the SnO 2 electron transporting layer (ETL), with excellent electron extraction and hole-blocking ability, offer significant advantages compared with high-temperature deposition methods. The optical, chemical, and electrical properties of the ALD SnO 2 layer and its influence on the device performance are investigated. It is found that surface passivation of SnO 2 is essential to reduce charge recombination at the perovskite and ETL interface and show that the fabricated planar perovskite solar cells exhibit high reproducibility, stability, and power conversion efficiency of 20%.

Substrate-Independent Epitaxial Growth of the Metal-Organic Framework MOF-508a.

PubMed

Wilson, M; Barrientos-Palomo, S N; Stevens, P C; Mitchell, N L; Oswald, G; Nagaraja, C M; Badyal, J P S

2018-01-31

Plasmachemical deposition is a substrate-independent method for the conformal surface functionalization of solid substrates. Structurally well-defined pulsed plasma deposited poly(1-allylimidazole) layers provide surface imidazole linker groups for the directed liquid-phase epitaxial (layer-by-layer) growth of metal-organic frameworks (MOFs) at room temperature. For the case of microporous [Zn (benzene-1,4-dicarboxylate)-(4,4'-bipyridine) 0.5 ] (MOF-508), the MOF-508a polymorph containing two interpenetrating crystal lattice frameworks undergoes orientated Volmer-Weber growth and displays CO 2 gas capture behavior at atmospheric concentrations in proportion to the number of epitaxially grown MOF-508 layers.

Method to planarize three-dimensional structures to enable conformal electrodes

DOEpatents

Nikolic, Rebecca J; Conway, Adam M; Graff, Robert T; Reinhardt, Catherine; Voss, Lars F; Shao, Qinghui

2012-11-20

Methods for fabricating three-dimensional PIN structures having conformal electrodes are provided, as well as the structures themselves. The structures include a first layer and an array of pillars with cavity regions between the pillars. A first end of each pillar is in contact with the first layer. A segment is formed on the second end of each pillar. The cavity regions are filled with a fill material, which may be a functional material such as a neutron sensitive material. The fill material covers each segment. A portion of the fill material is etched back to produce an exposed portion of the segment. A first electrode is deposited onto the fill material and each exposed segment, thereby forming a conductive layer that provides a common contact to each the exposed segment. A second electrode is deposited onto the first layer.

Template Synthesis of Nanostructured Polymeric Membranes by Inkjet Printing.

PubMed

Gao, Peng; Hunter, Aaron; Benavides, Sherwood; Summe, Mark J; Gao, Feng; Phillip, William A

2016-02-10

The fabrication of functional nanomaterials with complex structures has been serving great scientific and practical interests, but current fabrication and patterning methods are generally costly and laborious. Here, we introduce a versatile, reliable, and rapid method for fabricating nanostructured polymeric materials. The novel method is based on a combination of inkjet printing and template synthesis, and its utility and advantages in the fabrication of polymeric nanomaterials is demonstrated through three examples: the generation of polymeric nanotubes, nanowires, and thin films. Layer-by-layer-assembled nanotubes can be synthesized in a polycarbonate track-etched (PCTE) membrane by printing poly(allylamine hydrochloride) and poly(styrenesulfonate) sequentially. This sequential deposition of polyelectrolyte ink enables control over the surface charge within the nanotubes. By a simple change of the printing conditions, polymeric nanotubes or nanowires were prepared by printing poly(vinyl alcohol) in a PCTE template. In this case, the high-throughput nature of the method enables functional nanomaterials to be generated in under 3 min. Furthermore, we demonstrate that inkjet printing paired with template synthesis can be used to generate patterns comprised of chemically distinct nanomaterials. Thin polymeric films of layer-by-layer-assembled poly(allylamine hydrochloride) and poly(styrenesulfonate) are printed on a PCTE membrane. Track-etched membranes covered with the deposited thin films reject ions and can potentially be utilized as nanofiltration membranes. When the fabrication of these different classes of nanostructured materials is demonstrated, the advantages of pairing template synthesis with inkjet printing, which include fast and reliable deposition, judicious use of the deposited materials, and the ability to design chemically patterned surfaces, are highlighted.

Integrated power passives

NASA Technical Reports Server (NTRS)

Xie, Huikai (Inventor); Ngo, Khai D. T. (Inventor)

2013-01-01

A multi-layer film-stack and method for forming the multilayer film-stack is given where a series of alternating layers of conducting and dielectric materials are deposited such that the conducting layers can be selectively addressed. The use of the method to form integratable high capacitance density capacitors and complete the formation of an integrated power system-on-a-chip device including transistors, conductors, inductors, and capacitors is also given.

Evaporation Source for Deposition of Protective Layers inside Tubes

NASA Astrophysics Data System (ADS)

Musa, Geavit; Mustata, Ion; Dinescu, Gheorghe; Bajeu, George; Raiciu, Elena

1992-09-01

A heated cathode arc can be ignited in vacuum in the vapours of the anode material due to the accelerated electron beam from the cathode. A small assembly, consisting of an electron gun as the cathode and a refractory metal crucible, containing the material to be evaporated, as the anode, can be moved along the axis of the tube whose inside wall is to be covered with a protective layer. The vacuum arc ignited between the electrodes in the vapours of the evaporating anode material ensures a high deposition rate with low thermal energy transport to the tube wall. This new method can be used for the deposition of various metal layers inside different kinds of tubes (metallic, glass, ceramics or plastics).

CsPbBr 3 Solar Cells: Controlled Film Growth through Layer-by-Layer Quantum Dot Deposition

DOE PAGES

Hoffman, Jacob B.; Zaiats, Gary; Wappes, Isaac; ...

2017-10-25

All inorganic cesium lead bromide (CsPbBr 3) perovskite is a more stable alternative to methylammonium lead bromide (MAPbBr 3) for designing high open-circuit voltage solar cells and display devices. Poor solubility of CsBr in organic solvents makes typical solution deposition methods difficult to adapt for constructing CsPbBr 3 devices. Our layer-by-layer methodology, which makes use of CsPbBr 3 quantum dot (QD) deposition followed by annealing, provides a convenient way to cast stable films of desired thickness. The transformation from QDs into bulk during thermal annealing arises from the resumption of nanoparticle growth and not from sintering as generally assumed. Additionally,more » a large loss of organic material during the annealing process is mainly from 1-octadecene left during the QD synthesis. Utilizing this deposition approach for perovskite photovoltaics is examined using typical planar architecture devices. Devices optimized to both QD spin-casting concentration and overall CsPbBr 3 thickness produce champion devices that reach power conversion efficiencies of 5.5% with a V oc value of 1.4 V. Finally, the layered QD deposition demonstrates a controlled perovskite film architecture for developing efficient, high open-circuit photovoltaic devices.« less

CsPbBr 3 Solar Cells: Controlled Film Growth through Layer-by-Layer Quantum Dot Deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, Jacob B.; Zaiats, Gary; Wappes, Isaac

All inorganic cesium lead bromide (CsPbBr 3) perovskite is a more stable alternative to methylammonium lead bromide (MAPbBr 3) for designing high open-circuit voltage solar cells and display devices. Poor solubility of CsBr in organic solvents makes typical solution deposition methods difficult to adapt for constructing CsPbBr 3 devices. Our layer-by-layer methodology, which makes use of CsPbBr 3 quantum dot (QD) deposition followed by annealing, provides a convenient way to cast stable films of desired thickness. The transformation from QDs into bulk during thermal annealing arises from the resumption of nanoparticle growth and not from sintering as generally assumed. Additionally,more » a large loss of organic material during the annealing process is mainly from 1-octadecene left during the QD synthesis. Utilizing this deposition approach for perovskite photovoltaics is examined using typical planar architecture devices. Devices optimized to both QD spin-casting concentration and overall CsPbBr 3 thickness produce champion devices that reach power conversion efficiencies of 5.5% with a V oc value of 1.4 V. Finally, the layered QD deposition demonstrates a controlled perovskite film architecture for developing efficient, high open-circuit photovoltaic devices.« less

Influence of sputtering deposition parameters on electrical and optical properties of aluminium-doped zinc oxide thin films for photovoltaic applications

NASA Astrophysics Data System (ADS)

Krawczak, Ewelina; Agata, Zdyb; Gulkowski, Slawomir; Fave, Alain; Fourmond, Erwann

2017-11-01

Transparent Conductive Oxides (TCOs) characterized by high visible transmittance and low electrical resistivity play an important role in photovoltaic technology. Aluminum doped zinc oxide (AZO) is one of the TCOs that can find its application in thin film solar cells (CIGS or CdTe PV technology) as well as in other microelectronic applications. In this paper some optical and electrical properties of ZnO:Al thin films deposited by RF magnetron sputtering method have been investigated. AZO layers have been deposited on the soda lime glass substrates with use of variable technological parameters such as pressure in the deposition chamber, power applied and temperature during the process. The composition of AZO films has been investigated by EDS method. Thickness and refraction index of the deposited layers in dependence on certain technological parameters of sputtering process have been determined by spectroscopic ellipsometry. The measurements of transmittance and sheet resistance were also performed.

Effect of Ti seed layers on structure of self-organized epitaxial face-centered-cubic-Ag(001) oriented nanodots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamiko, M.; Nose, K.; Suenaga, R.

2013-12-28

The influence of Ti seed layers on the structure of self-organized Ag nanodots, obtained with a Ti seed-layer-assisted thermal agglomeration method, has been investigated. The samples were grown on MgO(001) single crystal substrates by RF magnetron sputter deposition. The samples were deposited at room temperature and post-annealed at 350 °C for 4 h while maintaining the chamber vacuum conditions. The results of atomic force microscopy (AFM) observations indicated that the insertion of the Ti seed layer (0.6–5.0 nm) between the MgO substrate and Ag layer promotes the agglomeration process, forming the nanodot array. Comparisons between the AFM images revealed thatmore » the size of the Ag nanodots was increased with an increase in the Ti seed layer thickness. The atomic concentration of the film surface was confirmed by X-ray photoelectron spectroscopy (XPS). The XPS result suggested that the nanodot surface mainly consisted of Ag. Moreover, X-ray diffraction results proved that the initial deposition of the Ti seed layer (0.6–5.0 nm) onto MgO(001) prior to the Ag deposition yielded high-quality fcc-Ag(001) oriented epitaxial nanodots. The optical absorbance spectra of the fabricated Ag nanodots with various Ti seed layer thicknesses were obtained in the visible light range.« less

Method for making circular tubular channels with two silicon wafers

DOEpatents

Yu, C.M.; Hui, W.C.

1996-11-19

A two-wafer microcapillary structure is fabricated by depositing boron nitride (BN) or silicon nitride (Si{sub 3}N{sub 4}) on two separate silicon wafers (e.g., crystal-plane silicon with [100] or [110] crystal orientation). Photolithography is used with a photoresist to create exposed areas in the deposition for plasma etching. A slit entry through to the silicon is created along the path desired for the ultimate microcapillary. Acetone is used to remove the photoresist. An isotropic etch, e.g., such as HF/HNO{sub 3}/CH{sub 3}COOH, then erodes away the silicon through the trench opening in the deposition layer. A channel with a half-circular cross section is then formed in the silicon along the line of the trench in the deposition layer. Wet etching is then used to remove the deposition layer. The two silicon wafers are aligned and then bonded together face-to-face to complete the microcapillary. 11 figs.

Ultra-high current density thin-film Si diode

DOEpatents

Wang; Qi

2008-04-22

A combination of a thin-film .mu.c-Si and a-Si:H containing diode structure characterized by an ultra-high current density that exceeds 1000 A/cm.sup.2, comprising: a substrate; a bottom metal layer disposed on the substrate; an n-layer of .mu.c-Si deposited the bottom metal layer; an i-layer of .mu.c-Si deposited on the n-layer; a buffer layer of a-Si:H deposited on the i-layer, a p-layer of .mu.c-Si deposited on the buffer layer; and a top metal layer deposited on the p-layer.

Nanocrystalline ferroelectric BaTiO3/Pt/fused silica for implants synthetized by pulsed laser deposition method

NASA Astrophysics Data System (ADS)

Jelínek, Miroslav; Drahokoupil, Jan; Jurek, Karel; Kocourek, Tomáš; Vaněk, Přemysl

2017-09-01

The thin-films of BaTiO3 (BTO)/Pt were prepared to test their potential as coatings for titanium-alloy implants. The nanocrystalline BTO/Pt bi-layers were successfully synthesized using fused silica as substrates. The bi-layers were prepared using KrF excimer laser ablation at substrate temperatures (Ts) ranging from 650 °C to 750 °C. The microstructure and composition of the deposits were investigated by scanning electron microscope, x-ray diffraction and wavelength dispersive x-ray spectroscopy methods. The electrical characterization of the Pt/BTO/Pt capacitors indicated ferroelectric-type response in BTO films containing (40-140) nm-sized grains. The technology, microstructure, and functional response of the layers are presented in detail.

Modulating the fixed charge density in silicon nitride films while monitoring the surface recombination velocity by photoluminescence imaging

NASA Astrophysics Data System (ADS)

Bazilchuk, Molly; Haug, Halvard; Marstein, Erik Stensrud

2015-04-01

Several important semiconductor devices such as solar cells and photodetectors may be fabricated based on surface inversion layer junctions induced by fixed charge in a dielectric layer. Inversion layer junctions can easily be fabricated by depositing layers with a high density of fixed charge on a semiconducting substrate. Increasing the fixed charge improves such devices; for instance, the efficiency of a solar cell can be substantially increased by reducing the surface recombination velocity, which is a function of the fixed charge density. Methods for increasing the charge density are therefore of interest. In this work, the fixed charge density in silicon nitride layers deposited by plasma enhanced chemical vapor deposition is increased to very high values above 1 × 1013 cm-2 after the application of an external voltage to a gate electrode. The effect of the fixed charge density on the surface recombination velocity was experimentally observed using the combination of capacitance-voltage characterization and photoluminescence imaging, showing a significant reduction in the surface recombination velocity for increasing charge density. The surface recombination velocity vs. charge density data was analyzed using a numerical device model, which indicated the presence of a sub-surface damage region formed during deposition of the layers. Finally, we have demonstrated that the aluminum electrodes used for charge injection may be chemically removed in phosphoric acid without loss of the underlying charge. The injected charge was shown to be stable for a prolonged time period, leading us to propose charge injection in silicon nitride films by application of soaking voltage as a viable method for fabricating inversion layer devices.

RBS, XRR and optical reflectivity measurements of Ti-TiO{sub 2} thin films deposited by magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drogowska, K.; Institute of Materials Science, Technische Universitaet Darmstadt, Petersenstrasse 23, 64287 Darmstadt; Tarnawski, Z., E-mail: tarnawsk@agh.edu.pl

2012-02-15

Highlights: Black-Right-Pointing-Pointer The single-, bi- and tri-layered films of Ti-TiO{sub 2} deposited onto Si(1 1 1) substrates. Black-Right-Pointing-Pointer Three methods RBS, XRR, optical reflectometer were used. Black-Right-Pointing-Pointer The real thickness of each layer was smaller than 50 nm. Black-Right-Pointing-Pointer Ti and TiO{sub 2} film-densities were slightly lower than the corresponding bulk values. -- Abstract: Single-, bi- and tri-layered films of Ti-TiO{sub 2} system were deposited by d.c. pulsed magnetron sputtering from metallic Ti target in an inert Ar or reactive Ar + O{sub 2} atmosphere. The nominal thickness of each layer was 50 nm. The chemical composition and its depthmore » profile were determined by Rutherford backscattering spectroscopy (RBS). Crystallographic structure was analysed by means of X-ray diffraction (XRD) at glancing incidence. X-ray reflectometry (XRR) was used as a complementary method for the film thickness and density evaluation. Modelling of the optical reflectivity spectra of Ti-TiO{sub 2} thin films deposited onto Si(1 1 1) substrates provided an independent estimate of the layer thickness. The combined analysis of RBS, XRR and reflectivity spectra indicated the real thickness of each layer less than 50 nm with TiO{sub 2} film density slightly lower than the corresponding bulk value. Scanning Electron Microscopy (SEM) cross-sectional images revealed the columnar growth of TiO{sub 2} layers. Thickness estimated directly from SEM studies was found to be in a good agreement with the results of RBS, XRR and reflectivity spectra.« less

Formation of Micro- and Nanostructures on the Nanotitanium Surface by Chemical Etching and Deposition of Titania Films by Atomic Layer Deposition (ALD)

PubMed Central

Nazarov, Denis V.; Zemtsova, Elena G.; Valiev, Ruslan Z.; Smirnov, Vladimir M.

2015-01-01

In this study, an integrated approach was used for the preparation of a nanotitanium-based bioactive material. The integrated approach included three methods: severe plastic deformation (SPD), chemical etching and atomic layer deposition (ALD). For the first time, it was experimentally shown that the nature of the etching medium (acidic or basic Piranha solutions) and the etching time have a significant qualitative impact on the nanotitanium surface structure both at the nano- and microscale. The etched samples were coated with crystalline biocompatible TiO2 films with a thickness of 20 nm by Atomic Layer Deposition (ALD). Comparative study of the adhesive and spreading properties of human osteoblasts MG-63 has demonstrated that presence of nano- and microscale structures and crystalline titanium oxide on the surface of nanotitanium improve bioactive properties of the material. PMID:28793716

Substrate-insensitive atomic layer deposition of plasmonic titanium nitride films

DOE PAGES

Yu, Ing-Song; Cheng, Hsyi-En; Chang, Chun-Chieh; ...

2017-02-06

The plasmonic properties of titanium nitride (TiN) films depend on the type of substrate when using typical deposition methods such as sputtering. We show atomic layer deposition (ALD) of TiN films with very weak dependence of plasmonic properties on the substrate, which also suggests the prediction and evaluation of plasmonic performance of TiN nanostructures on arbitrary substrates under a given deposition condition. Our results also observe that substrates with more nitrogen-terminated (N-terminated) surfaces will have significant impact on the deposition rate as well as the film plasmonic properties. Furthermore, we illustrate that the plasmonic properties of ALD TiN films canmore » be tailored by simply adjusting the deposition and/or post-deposition annealing temperatures. These characteristics and the capability of conformal coating make ALD TiN films on templates ideal for applications that require the fabrication of complex 3D plasmonic nanostructures.« less

Effect of swift heavy ion irradiation on structural and opto-electrical properties of bi-layer CdS-Bi2S3 thin films prepared by solution growth technique at room temperature

NASA Astrophysics Data System (ADS)

Shaikh, Shaheed U.; Siddiqui, Farha Y.; Desale, Deepali J.; Ghule, Anil V.; Singh, Fouran; Kulriya, Pawan K.; Sharma, Ramphal

2015-01-01

CdS-Bi2S3 bi-layer thin films have been deposited by chemical bath deposition method on Indium Tin Oxide glass substrate at room temperature. The as-deposited thin films were annealed at 250 °C in an air atmosphere for 1 h. An air annealed thin film was irradiated using Au9+ ions with the energy of 120 MeV at fluence 5×1012 ions/cm2 using tandem pelletron accelerator. The irradiation induced modifications were studied using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Raman spectroscopy, UV spectroscopy and I-V characteristics. XRD study reveals that the as-deposited thin films were nanocrystalline in nature. The decrease in crystallite size, increase in energy band gap and resistivity were observed after irradiation. Results are explained on the basis of energy deposited by the electronic loss after irradiation. The comparative results of as-deposited, air annealed and irradiated CdS-Bi2S3 bi-layer thin films are presented.

[Observation of ozone dry deposition in the field of winter wheat.

PubMed

Li, Shuo; Zheng, You Fei; Wu, Rong Jun; Yin, Ji Fu; Xu, Jing Xin; Zhao, Hui; Sun, Jian

2016-06-01

Ozone is one of the main atmospheric pollutants over surface layer, and its increasing surface ozone concentration and its impact on main crops have become the focus of the public. In order to explore ozone deposition law and environmental factors influencing ozone deposition process, this study used the micrometeorological methods and carried out the experiment under natural conditions. The results showed that during the observational period (the vigorously growing season of wheat), the mean value of ozone flux was -0.35 μg·m -2 ·s -1 (the negative sign indicated that the deposition direction was toward the ground). The mean rate of ozone deposition was 0.55 cm·s -1 . The mean value of aerodynamic resistance was 30 s·m -1 , the mean value of sub-layer resistance was 257 s·m -1 , and that of the canopy layer stomatic resistance was 163 s·m -1 . All the test parameters presented distinct diurnal fluctuation. The ozone deposition resistance was influenced by friction velocity, solar radiation velocity, temperature, relative humidity and other factors.

Control of thermal deformation in dielectric mirrors using mechanical design and atomic layer deposition.

PubMed

Gabriel, Nicholas T; Kim, Sangho S; Talghader, Joseph J

2009-07-01

A mechanical design technique for optical coatings that simultaneously controls thermal deformation and optical reflectivity is reported. The method requires measurement of the refractive index and thermal stress of single films prior to the design. Atomic layer deposition was used for deposition because of the high repeatability of the film constants. An Al2O3/HfO2 distributed Bragg reflector was deposited with a predicted peak reflectivity of 87.9% at 542.4 nm and predicted edge deformation of -360 nm/K on a 10 cm silicon substrate. The measured peak reflectivity was 85.7% at 541.7 nm with an edge deformation of -346 nm/K.

Characterisation of well-adhered ZrO2 layers produced on structured reactors using the sonochemical sol-gel method

NASA Astrophysics Data System (ADS)

Jodłowski, Przemysław J.; Chlebda, Damian K.; Jędrzejczyk, Roman J.; Dziedzicka, Anna; Kuterasiński, Łukasz; Sitarz, Maciej

2018-01-01

The aim of this study was to obtain thin zirconium dioxide coatings on structured reactors using the sonochemical sol-gel method. The preparation method of metal oxide layers on metallic structures was based on the synergistic combination of three approaches: the application of ultrasonic irradiation during the synthesis of Zr sol-gel based on a precursor solution containing zirconium(IV) n-propoxide, the addition of stabilszing agents, and the deposition of ZrO2 on the metallic structures using the dip-coating method. As a result, dense, uniform zirconium dioxide films were obtained on the FeCrAlloy supports. The structured reactors were characterised by various physicochemical methods, such as BET, AFM, EDX, XRF, XRD, XPS and in situ Raman spectroscopy. The results of the structural analysis by Raman and XPS spectroscopy confirmed that the metallic surface was covered by a ZrO2 layer without any impurities. SEM/EDX mapping revealed that the deposited ZrO2 covered the metallic support uniformly. The mechanical and high temperature tests showed that the developed ultrasound assisted sol-gel method is an efficient way to obtain thin, well-adhered zirconium dioxide layers on the structured reactors. The prepared metallic supports covered with thin ZrO2 layers may be a good alternative to layered structured reactors in several dynamics flow processes, for example for gas exhaust abatement.

Strained-layer epitaxy of germanium-silicon alloys

NASA Astrophysics Data System (ADS)

Bean, J. C.

1985-10-01

Strained-layer epitaxy is presented as a developing technique for combining Si with other materials in order to obtain semiconductors with enhanced electronic properties. The method involves applying layers sufficiently thin so that the atoms deposited match the bonding configurations of the substrate crystal. When deposited on Si, a four-fold bonding pattern is retained, with a lowered interfacial energy and augmented stored strain energy in the epitaxial layer. The main problem which remains is building an epitaxial layer thick enough to yield desired epitaxial properties while avoiding a reversion to an unstrained structure. The application of a Ge layer to Si using MBE is described, along with the formation of heterojunction multi-layer superlattices, which can reduce the dislocation effects in some homojunctions. The technique shows promise for developing materials of use as bipolar transistors, optical detectors and fiber optic transmission devices.

Structure and Distribution of Components in the Working Layer Upon Reconditioning of Parts by Electric-Arc Metallization

NASA Astrophysics Data System (ADS)

Skoblo, T. S.; Vlasovets, V. M.; Moroz, V. V.

2001-11-01

Reliable data on the structure of the deposited layer are very important due to the considerable instability of the process of deposition of coatings by the method of electric-arc metallization and the strict requirements for reconditioned crankshafts. The present paper is devoted to the structure of coatings obtained from powder wire based on ferrochrome-aluminum with additional alloying elements introduced into the charge.

Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

DOEpatents

Wu, Xuanzhi; Coutts, Timothy J.; Sheldon, Peter; Rose, Douglas H.

1999-01-01

A photovoltaic device having a substrate, a layer of Cd.sub.2 SnO.sub.4 disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd.sub.2 SnO.sub.4, and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd.sub.2 SnO.sub.4 layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd.sub.2 SnO.sub.4, and depositing an electrically conductive film onto the thin film of semiconductor materials.

Anticorrosion efficiency of ultrasonically deposited silica coatings on titanium

NASA Astrophysics Data System (ADS)

Ertaş, Fatma Sinem; Kaş, Recep; Mikó, Annamária; Birer, Özgür

2013-07-01

We utilized high intensity ultrasound to prepare coatings of silica and organically modified silica composed of multiple layers of densely packed nanoparticles. Ultrasound was used to collide nanoparticles onto an activated titanium surface with high speed. Large areas could be homogeneously coated by this method. These coatings were characterized by spectroscopy and microscopy methods and the anticorrosion efficiency in NaCl solution was evaluated by electrochemical measurements. The results indicated that the composite coatings provided good quality barrier layer on bare titanium and decreased the anodic corrosion rate. It was found that increase in the organic content of the coating shifted the passivation potential towards more positive direction. The comparison of the impedance results recorded at the corrosion potential pointed out that in each case a good quality barrier layer was formed on the titanium surface. The outstanding corrosion resistance of the composite coatings with only ~200 nm thickness shows that ultrasound assisted deposition can be a competitive method to obtain corrosion protective layers.

RHEED oscillations in spinel ferrite epitaxial films grown by conventional planar magnetron sputtering

NASA Astrophysics Data System (ADS)

Ojima, T.; Tainosho, T.; Sharmin, S.; Yanagihara, H.

2018-04-01

Real-time in situ reflection high energy electron diffraction (RHEED) observations of Fe3O4, γ-Fe2O3, and (Co,Fe)3O4 films on MgO(001) substrates grown by a conventional planar magnetron sputtering was studied. The change in periodical intensity of the specular reflection spot in the RHEED images of three different spinel ferrite compounds grown by two different sputtering systems was examined. The oscillation period was found to correspond to the 1/4 unit cell of each spinel ferrite, similar to that observed in molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) experiments. This suggests that the layer-by-layer growth of spinel ferrite (001) films is general in most physical vapor deposition (PVD) processes. The surfaces of the films were as flat as the surface of the substrate, consistent with the observed layer-by-layer growth process. The observed RHEED oscillation indicates that even a conventional sputtering method can be used to control film thickness during atomic layer depositions.

Study of the interaction mechanisms between absorbed NO{sub 2} and por-Si/SnO{sub x} nanocomposite layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotov, V. V.; Kan, V. E., E-mail: kan@obisp.oscsbras.ru; Makushenko, R. K.

2013-10-15

The interaction mechanisms between NO{sub 2} molecules and the surface of por-Si/SnO{sub x} nanocomposites obtained by magnetron deposition and chemical vapor deposition (CVD) are studied by infrared absorption spectroscopy and electron paramagnetic resonance methods. The observed increase in the free carrier concentration in the por-Si/SnO{sub x} nanocomposite layers is explained by a change in the charge state of P{sub b} centers due to the formation of neutral 'surface defect-adsorbed NO{sub 2} molecule' complexes with free carrier generation in the crystallite bulk. In the nanocomposite layers grown by the CVD method, the increase in the free hole concentration during NO{sub 2}more » adsorption is much less pronounced in comparison with the composite grown by magnetron deposition, which is caused by the competing interaction channel of NO{sub 2} molecules with electrically neutral P{sub b} centers.« less

Gas sensing properties of very thin TiO2 films prepared by atomic layer deposition (ALD)

NASA Astrophysics Data System (ADS)

Boyadjiev, S.; Georgieva, V.; Vergov, L.; Baji, Zs; Gáber, F.; Szilágyi, I. M.

2014-11-01

Very thin titanium dioxide (TiO2) films of less than 10 nm were deposited by atomic layer deposition (ALD) in order to study their gas sensing properties. Applying the quartz crystal microbalance (QCM) method, prototype structures with the TiO2 ALD deposited thin films were tested for sensitivity to NO2. Although being very thin, the films were sensitive at room temperature and could register low concentrations as 50-100 ppm. The sorption is fully reversible and the films seem to be capable to detect for long term. These initial results for very thin ALD deposited TiO2 films give a promising approach for producing gas sensors working at room temperature on a fast, simple and cost-effective technology.

Coincident site lattice-matched growth of semiconductors on substrates using compliant buffer layers

DOEpatents

Norman, Andrew

2016-08-23

A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a silicon substrate using a compliant buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The compliant buffer material and semiconductor materials may be deposited using coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The coincident site lattice matching epitaxial process, as well as the use of a ductile buffer material, reduce the internal stresses and associated crystal defects within the deposited semiconductor materials fabricated using the disclosed method. As a result, the semiconductor devices provided herein possess enhanced performance characteristics due to a relatively low density of crystal defects.

Study of iron deposit using seismic refraction and resistivity in Carajás Mineral Province, Brazil

NASA Astrophysics Data System (ADS)

Nogueira, Pedro Vencovsky; Rocha, Marcelo Peres; Borges, Welitom Rodrigues; Silva, Adalene Moreira; Assis, Luciano Mozer de

2016-10-01

This work comprises the acquisition, processing and interpretation of 2D seismic shallow refraction (P-wave) and resistivity profiles located in the iron ore deposit of N4WS, Carajás Mineral Province (CMP), northern Brazil. The geophysical methods were used to identify the boundaries of the iron ore deposit. Another objective was to evaluate the potentiality of these geophysical methods in that geological context. In order to validate the results, the geophysical lines were located to match a geological borehole line. For the seismic refraction, we used 120 channels, spaced by 10 m, in a line of 1190 m, with seven shot points. The resistivity method used in the acquisition was the electrical resistivity imaging, with pole-pole array, in order to reach greater depths. The resistivity line had a length of 1430 m, with 10 m spacing between electrodes. The seismic results produced a model with two distinct layers. Based on the velocities values, the first layer was interpreted as altered rocks, and the second layer as more preserved rocks. It was not possible to discriminate different lithologies with the seismic method inside each layer. From the resistivity results, a zone of higher resistivity (> 3937 Ω·m) was interpreted as iron ore, and a region of intermediate resistivity (from 816 to 2330 Ω·m) as altered rocks. These two regions represent the first seismic layer. On the second seismic layer, an area with intermediated resistivity values (from 483 to 2330 Ω·m) was interpreted as mafic rocks, and the area with lower resistivity (< 483 Ω·m) as jaspilite. Our results were compared with geological boreholes and show reasonable correlation, suggesting that the geophysical anomalies correspond to the main variations in composition and physical properties of rocks.

Method to fabricate multi-level silicon-based microstructures via use of an etching delay layer

DOEpatents

Manginell, Ronald P.; Schubert, W. Kent; Shul, Randy J.

2005-08-16

New methods for fabrication of silicon microstructures have been developed. In these methods, an etching delay layer is deposited and patterned so as to provide differential control on the depth of features being etched into a substrate material. Structures having features with different depth can be formed thereby in a single etching step.

Method for producing nanowire-polymer composite electrodes

DOEpatents

Pei, Qibing; Yu, Zhibin

2017-11-21

A method for producing flexible, nanoparticle-polymer composite electrodes is described. Conductive nanoparticles, preferably metal nanowires or nanotubes, are deposited on a smooth surface of a platform to produce a porous conductive layer. A second application of conductive nanoparticles or a mixture of nanoparticles can also be deposited to form a porous conductive layer. The conductive layer is then coated with at least one coating of monomers that is polymerized to form a conductive layer-polymer composite film. Optionally, a protective coating can be applied to the top of the composite film. In one embodiment, the monomer coating includes light transducing particles to reduce the total internal reflection of light through the composite film or pigments that absorb light at one wavelength and re-emit light at a longer wavelength. The resulting composite film has an active side that is smooth with surface height variations of 100 nm or less.

Direct deposit laminate nanocomposites with enhanced propellent properties.

PubMed

Li, Xiangyu; Guerieri, Philip; Zhou, Wenbo; Huang, Chuan; Zachariah, Michael R

2015-05-06

One of the challenges in the use of energetic nanoparticles within a polymer matrix for propellant applications is obtaining high particle loading (high energy density) while maintaining mechanical integrity and reactivity. In this study, we explore a new strategy that utilizes laminate structures. Here, a laminate of alternating layers of aluminum nanoparticle (Al-NPs)/copper oxide nanoparticle (CuO-NPs) thermites in a polyvinylidene fluoride (PVDF) reactive binder, with a spacer layer of PVDF was fabricated by a electrospray layer-by-layer deposition method. The deposited layers containing up to 60 wt % Al-NPs/CuO-NPs thermite are found to be uniform and mechanically flexible. Both the reactive and mechanical properties of laminate significantly outperformed the single-layer structure with the same material composition. These results suggest that deploying a multilayer laminate structure enables the incorporation of high loadings of energetic materials and, in some cases, enhances the reactive properties over the corresponding homogeneous structure. These results imply that an additive manufacturing approach may yield significant advantages in developing a tailored architecture for advanced propulsion systems.

Direct observation of inversion capacitance in p-type diamond MOS capacitors with an electron injection layer

NASA Astrophysics Data System (ADS)

Matsumoto, Tsubasa; Kato, Hiromitsu; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Yamasaki, Satoshi; Imura, Masataka; Ueda, Akihiro; Inokuma, Takao; Tokuda, Norio

2018-04-01

The electrical properties of Al2O3/p-type diamond (111) MOS capacitors were studied with the goal of furthering diamond-based semiconductor research. To confirm the formation of an inversion layer in the p-type diamond body, an n-type layer for use as a minority carrier injection layer was selectively deposited onto p-type diamond. To form the diamond MOS capacitors, Al2O3 was deposited onto OH-terminated diamond using atomic layer deposition. The MOS capacitor showed clear inversion capacitance at 10 Hz. The minority carrier injection from the n-type layer reached the inversion n-channel diamond MOS field-effect transistor (MOSFET). Using the high-low frequency capacitance method, the interface state density, D it, within an energy range of 0.1-0.5 eV from the valence band edge energy, E v, was estimated at (4-9) × 1012 cm-2 eV-1. However, the high D it near E v remains an obstacle to improving the field effect mobility for the inversion p-channel diamond MOSFET.

Repair of high performance multilayer coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaines, D.P.; Ceglio, N.M.; Vernon, S.P.

1991-07-01

Fabrication and environmental damage issues may require that the multilayer x-ray reflection coatings used in soft x-ray projection lithography be replaced or repaired. Two repair strategies were investigated. The first was to overcoat defective multilayers with a new multilayer. The feasibility of this approach was demonstrated by depositing high reflectivity (61% at 130 {Angstrom}) molybdenum silicon (Mo/Si) multilayers onto fused silica figured optics that had already been coated with a Mo/Si multilayer. Because some types of damage mechanisms and fabrication errors are not repairable by this method, a second method of repair was investigated. The multilayer was stripped from themore » optical substrate by etching a release layer which was deposited onto the substrate beneath the multilayer. The release layer consisted of a 1000 {Angstrom} aluminum film deposited by ion beam sputtering or by electron beam evaporation, with a 300 {Angstrom} SiO{sub 2} protective overcoat. The substrates were superpolished zerodur optical flats. The normal incidence x-ray reflectivity of multilayers deposited on these aluminized substrates was degraded, presumably due to the roughness of the aluminum films. Multilayers, and the underlying release layers, have been removed without damaging the substrates.« less

Method for measuring and controlling beam current in ion beam processing

DOEpatents

Kearney, Patrick A.; Burkhart, Scott C.

2003-04-29

A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.

Efficiencies of Dye-Sensitized Solar Cells using Ferritin-Encapsulated Quantum Dots with Various Staining Methods

NASA Astrophysics Data System (ADS)

Perez, Luis

Dye-sensitized solar cells (DSSC) have the potential to replace traditional and cost-inefficient crystalline silicon or ruthenium solar cells. This can only be accomplished by optimizing DSSC's energy efficiency. One of the major components in a dye-sensitized solar cell is the porous layer of titanium dioxide. This layer is coated with a molecular dye that absorbs sunlight. The research conducted for this paper focuses on the different methods used to dye the porous TiO2 layer with ferritin-encapsulated quantum dots. Multiple anodes were dyed using a method known as SILAR which involves deposition through alternate immersion in two different solutions. The efficiencies of DSSCs with ferritin-encapsulated lead sulfide dye deposited using SILAR were subsequently compared against the efficiencies produced by cells using the traditional immersion method. It was concluded that both methods resulted in similar efficiencies (? .074%) however, the SILAR method dyed the TiO2 coating significantly faster than the immersion method. On a related note, our experiments concluded that conducting 2 SILAR cycles yields the highest possible efficiency for this particular binding method. National Science Foundation.

Modification of surfaces of silver nanoparticles for controlled deposition of silicon, manganese, and titanium dioxides

NASA Astrophysics Data System (ADS)

Apostolova, Tzveta; Obreshkov, B. D.; Ionin, A. A.; Kudryashov, S. I.; Makarov, S. V.; Mel'nik, N. N.; Rudenko, A. A.

2018-01-01

In this work we show that nanometric-thick layers of SiO2, MnO2, and TiO2 may be effectively deposited on various silver nanoparticles (including cubic Ag nanoparticles) covered by a very thin (below 0.4 nm) layer of silver sulphide. The background in Raman measurements generated by sulphide-protected Ag nanoparticles is significantly smaller than that for analogous Ag nanoparticles protected by a monolayer formed from alkanethiols - depositing alkanethiols on a surface of anisotropic silver nanoparticles is the current standard method used for protecting a surface of Ag nanoparticles before depositing a layer of silica. Because of significantly smaller generated Raman background, Ag@SiO2 nanostructures with an Ag2S linkage layer between the silver core and the silica shell are very promising low-background electromagnetic nanoresonators for carrying out Raman analysis of various surfaces - especially using what is known as shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). Sample SHINERS analyses of various surfaces (including pesticide-contaminated surfaces of tomatoes) using cubic-Ag@SiO2 nanoparticles as electromagnetic nanoresonators are also presented.

Comparison of the Al back contact deposited by sputtering, e-beam, or thermal evaporation for inverted perovskite solar cells

NASA Astrophysics Data System (ADS)

Wahl, Tina; Hanisch, Jonas; Ahlswede, Erik

2018-04-01

In this work, we present inverted perovskite solar cells with Al top electrodes, which were deposited by three different methods. Besides the widely used thermal evaporation of Al, we also used the industrially important high deposition rate processes sputtering and electron beam evaporation for aluminium electrodes and examined the influence of the deposition method on the solar cell performance. The current-voltage characteristics of as grown solar cells with sputtered and e-beam Al electrode show an s-shape due to damage done to the organic electronic transport layers (ETL) during Al deposition. It can be cured by a short annealing step at a moderate temperature so that fill factors  >60% and power conversion efficiencies of almost 12% with negligible hysteresis can be achieved. While solar cells with thermally evaporated Al electrode do not show an s-shape, they also exhibit a clear improvement after a short annealing step. In addition, we varied the thickness of the ETL consisting of a double layer ([6,6]-Phenyl-C61-butyric acid methyl ester and bathocuproine) and investigated the influence on the solar cell parameters for the three different Al deposition methods, which showed distinct dependencies on ETL thickness.

Epitaxial growth of silicon for layer transfer

DOEpatents

Teplin, Charles; Branz, Howard M

2015-03-24

Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

Investigation of Ni@CoO core-shell nanoparticle films synthesized by sequential layer deposition

NASA Astrophysics Data System (ADS)

Spadaro, M. C.; Luches, P.; Benedetti, F.; Valeri, S.; Turchini, S.; Bertoni, G.; Ferretti, A. M.; Capetti, E.; Ponti, A.; D'Addato, S.

2017-02-01

Films of Ni@CoO core-shell nanoparticles (NP Ni core size d ≈ 11 nm) have been grown on Si/SiOx and lacey carbon supports, by a sequential layer deposition method: a first layer of CoO was evaporated on the substrate, followed by the deposition of a layer of pre-formed, mass-selected Ni NPs, and finally an overlayer of CoO was added. The Ni NPs were formed by a magnetron gas aggregation source, and mass selected with a quadrupole mass filter. The morphology of the films was investigated with Scanning Electron Microscopy and Scanning Transmission Electron Microscopy. The Ni NP cores have a shape compatible with McKay icosahedron, caused by multitwinning occurring during their growth in the source, and the Ni NP layer shows the typical random paving growth mode. After the deposition of the CoO overlayer, CoO islands are observed, gradually extending and tending to merge with each other, with the formation of shells that enclose the Ni NP cores. In situ X-ray Photoelectron Spectroscopy showed that a few Ni atomic layers localized at the core-shell interface are oxidized, hinting at the possibility of creating an intermediate NiO shell between Ni and CoO, depending on the deposition conditions. Finally, X-ray Magnetic Circular Dichroism at the Ni L2,3 absorption edge showed the presence of magnetization at room temperature even at remanence, revealing the possibility of magnetic stabilization of the NP film.

The Influence of Deposition Methods of Support Layer on Cordierite Substrate on the Characteristics of a MnO2–NiO–Co3O4/Ce0.2Zr0.8O2/Cordierite Three Way Catalyst

PubMed Central

Pham, Phuong Thi Mai; Le, Minh Thang; Nguyen, Tien The; Bruneel, Els; Van Driessche, Isabel

2014-01-01

This paper compares different coating methods (in situ solid combustion, hybrid deposition, secondary growth on seed, suspension, double deposition of wet impregnation and suspension) to deposit Ce0.2Zr0.8O2 mixed oxides on cordierite substrates, for use as a three way catalyst. Among them, the double deposition was proven to be the most efficient one. The coated sample shows a BET (Brunauer–Emmett–Teller) surface area of 25 m2/g, combined with a dense and crack free surface. The catalyst with a layer of MnO2–NiO–Co3O4 mixed oxides on top of the Ce0.2Zr0.8O2/cordierite substrate prepared by this method exhibits good activity for the treatment of CO, NO and C3H6 in exhaust gases (CO conversion of 100% at 250 °C, C3H6 conversion of 100% at 400 °C and NO conversion of 40% at 400 °C). PMID:28788189

X-ray lithography masking

NASA Technical Reports Server (NTRS)

Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

1998-01-01

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

Mitigation of substrate defects in reflective reticles using sequential coating and annealing

DOEpatents

Mirkanimi, Paul B.

2002-01-01

A buffer-layer to minimize the size of defects on a reticle substrate prior to deposition of a reflective coating on the substrate. The buffer-layer is formed by either a multilayer deposited on the substrate or by a plurality of sequentially deposited and annealed coatings deposited on the substrate. The plurality of sequentially deposited and annealed coating may comprise multilayer and single layer coatings. The multilayer deposited and annealed buffer layer coatings may be of the same or different material than the reflecting coating thereafter deposited on the buffer-layer.

Growing High-Quality InAs Quantum Dots for Infrared Lasers

NASA Technical Reports Server (NTRS)

Qiu, Yueming; Uhl, David

2004-01-01

An improved method of growing high-quality InAs quantum dots embedded in lattice-matched InGaAs quantum wells on InP substrates has been developed. InAs/InGaAs/InP quantum dot semiconductor lasers fabricated by this method are capable of operating at room temperature at wavelengths greater than or equal to 1.8 mm. Previously, InAs quantum dot lasers based on InP substrates have been reported only at low temperature of 77 K at a wavelength of 1.9 micrometers. In the present method, as in the prior method, one utilizes metalorganic vapor phase epitaxy to grow the aforementioned semiconductor structures. The development of the present method was prompted in part by the observation that when InAs quantum dots are deposited on an InGaAs layer, some of the InAs in the InGaAs layer becomes segregated from the layer and contributes to the formation of the InAs quantum dots. As a result, the quantum dots become highly nonuniform; some even exceed a critical thickness, beyond which they relax. In the present method, one covers the InGaAs layer with a thin layer of GaAs before depositing the InAs quantum dots. The purpose and effect of this thin GaAs layer is to suppress the segregation of InAs from the InGaAs layer, thereby enabling the InAs quantum dots to become nearly uniform (see figure). Devices fabricated by this method have shown near-room-temperature performance.

Development of Long REBCO with BMO Coated Conductors by PLD Method with High Production Rate

NASA Astrophysics Data System (ADS)

Ibi, A.; Yoshida, T.; Taneda, T.; Yoshizumi, M.; Izumi, T.; Shiohara, Y.

We have been developing long REBa2Cu3O7-δ (RE: Y, Gd and Eu etc.) with BaMO3 (M: Zr, Sn and Hf etc.) coated conductors by the combination of the ion-beam assisted deposition (IBAD) and the pulsed laser deposition (PLD) methods. REBa2Cu3O7-δ with BaMO3 coated conductors showed high in-field performance, therefore, these coated conductors could be expected for the industrial and commercial applications at high temperatures in magnetic fields. However, to realize the low production cost for long REBa2Cu3O7-δ with BaMO3 coated conductors, improvement of the production rate of the REBa2Cu3O7-δ layers containing BaMO3 rods with maintaining high superconducting properties is required. To solve these problems, we have tried deposition of the REBa2Cu3O7-δ layers with high superconducting properties by the PLD method with high production rate. As a result, we have successfully fabricated EuBa2Cu3O7-δ layers containing BaHfO3 rods with high in-field Jc and Ic by the PLD method with high production rate. This EuBa2Cu3O7-δ with BaHfO3 coated conductor exhibit a high Ic value of 412 and 48.7 A/cm-width at 77 K in self-field and 3 T, respectively at the deposition rate of about 40 μm/h and the production rate of 10 m/h for a 1.35 μm EuBCO layer thick.

Calculation and experimental determination of the geometric parameters of the coatings by laser cladding

NASA Astrophysics Data System (ADS)

Birukov, V. P.; Fichkov, A. A.

2017-12-01

In the present work the experiments on laser cladding of powder Fe-B-Cr-6-2 on samples of steel 20. Metallographic studies of geometric parameters of deposited layers and the depth of the heat affected zone (HAZ). Using is the method of full factorial experiment (FFE) mathematical dependences of the geometrical sizes of the deposited layers of processing modes. Deviation of calculated values from experimental data is not more than 3%.

Friction- and wear-reducing coating

DOEpatents

Zhu, Dong [Farmington Hills, MI; Milner, Robert [Warren, MI; Elmoursi, Alaa AbdelAzim [Troy, MI

2011-10-18

A coating includes a first layer of a ceramic alloy and a second layer disposed on the first layer and including carbon. The coating has a hardness of from 10 to 20 GPa and a coefficient of friction of less than or equal to 0.12. A method of coating a substrate includes cleaning the substrate, forming the first layer on the substrate, and depositing the second layer onto the first layer to thereby coat the substrate.

Semipermeable polymers and method for producing same

DOEpatents

Buschmann, Wayne E [Boulder, CO

2012-04-03

A polyamide membrane comprising reaction product of an anhydrous solution comprising an anhydrous solvent, at least one polyfunctional secondary amine and a pre-polymer deposition catalyst; and an anhydrous, organic solvent solution comprising a polyfunctional aromatic amine-reactive reactant comprising one ring. A composite semipermeable membrane comprising the polyamide membrane on a porous support. A method of making a composite semipermeable membrane by coating a porous support with an anhydrous solution comprising an anhydrous solvent, a polyfunctional secondary amine and a pre-polymer deposition catalyst, to form an activated pre-polymer layer on the porous support and contacting the activated pre-polymer layer with an anhydrous, organic solvent solution comprising a polyfunctional amine-reactive reactant to interfacially condense the amine-reactive reactant with the polyfunctional secondary amine, thereby forming a cross-linked, interfacial polyamide layer on the porous support. A method of impregnating a composite semipermeable membrane with nanoparticles selected from heavy metals and/or oxides of heavy metals.

Method of bonding silver to glass and mirrors produced according to this method

DOEpatents

Pitts, J.R.; Thomas, T.M.; Czanderna, A.W.

1984-07-31

A method for adhering silver to a glass substrate for producing mirrors includes attaining a silicon enriched substrate surface by reducing the oxygen therein in a vacuum and then vacuum depositing a silver layer onto the silicon enriched surface. The silicon enrichment can be attained by electron beam bombardment, ion beam bombardment, or neutral beam bombardment. It can also be attained by depositing a metal, such as aluminum, on the substrate surface, allowing the metal to oxidize by pulling oxygen from the substrate surface, thereby leaving a silicon enriched surface, and then etching or eroding the metal oxide layer away to expose the silicon enriched surface. Ultraviolet rays can be used to maintain dangling silicon bonds on the enriched surface until covalent bonding with the silver can occur. This disclosure also includes encapsulated mirrors with diffusion layers built therein. One of these mirrors is assembled on a polymer substrate.

Method of bonding silver to glass and mirrors produced according to this method

DOEpatents

Pitts, John R.; Thomas, Terence M.; Czanderna, Alvin W.

1985-01-01

A method for adhering silver to a glass substrate for producing mirrors includes attaining a silicon enriched substrate surface by reducing the oxygen therein in a vacuum and then vacuum depositing a silver layer onto the silicon enriched surface. The silicon enrichment can be attained by electron beam bombardment, ion beam bombardment, or neutral beam bombardment. It can also be attained by depositing a metal, such as aluminum, on the substrate surface, allowing the metal to oxidize by pulling oxygen from the substrate surface, thereby leaving a silicon enriched surface, and then etching or eroding the metal oxide layer away to expose the silicon enriched surface. Ultraviolet rays can be used to maintain dangling silicon bonds on the enriched surface until covalent bonding with the silver can occur. This disclosure also includes encapsulated mirrors with diffusion layers built therein. One of these mirrors is assembled on a polymer substrate.

Capacitance-voltage characterization of Al/Al2O3/PVA-PbSe MIS diode

NASA Astrophysics Data System (ADS)

Gawri, Isha; Sharma, Mamta; Jindal, Silky; Singh, Harpreet; Tripathi, S. K.

2018-05-01

The present paper reports the capacitance-voltage characterization of Al/Al2O3/PVA-PbSe MIS diode using chemical bath deposition method. Here anodic alumina layer prepared using electrolytic deposition method on Al substrate is used as insulating material. Using the capacitance-voltage variation at a fixed frequency, the different parameters such as Depletion layer width, Barrier height, Built-in voltage and Carrier concentration has been calculated at room temperature as well as at temperature range from 123 K to 323 K. With the increase in temperature the barrier height and depletion layer width follow a decreasing trend. Therefore, the capacitance-voltage characterization at different temperatures characterization provides strong evidence that the properties of MIS diode are primarily affected by diode parameters.

Thermoelectric properties of Zn4Sb3/CeFe(4-x)CoxSb12 nano-layered superlattices modified by MeV Si ion beam

NASA Astrophysics Data System (ADS)

Budak, S.; Guner, S.; Minamisawa, R. A.; Muntele, C. I.; Ila, D.

2014-08-01

We prepared multilayers of superlattice thin film system with 50 periodic alternating nano-layers of semiconducting half-Heusler β-Zn4Sb3 and skutterudite CeFe2Co2Sb12 compound thin films using ion beam assisted deposition (IBAD) with Au layers deposited on both sides as metal contacts. The deposited multilayer thin films have alternating layers about 5 nm thick. The total thickness of the multilayer system is 275 nm. The superlattices were then bombarded by 5 MeV Si ion at six different fluences to form nano-cluster structures. The film thicknesses and composition were monitored by Rutherford backscattering spectrometry (RBS) before and after MeV ion bombardment. We have measured the thermoelectric efficiency, Figure of Merit ZT, of the fabricated device by measuring the cross plane thermal conductivity by the 3rd harmonic (3ω) method, the cross plane Seebeck coefficient, and the electrical conductivity using the van der Pauw method before and after the MeV ion bombardments. We reached the remarkable thermoelectric Figure of Merit results at optimal fluences.

Designing optical metamaterial with hyperbolic dispersion based on Al:ZnO/ZnO nano-layered structure using Atomic Layer Deposition technique

DOE PAGES

Kelly, Priscilla; Liu, Mingzhao; Kuznetsova, Lyuba

2016-04-07

In this study, nano-layered Al:ZnO/ZnO hyperbolic dispersion metamaterial with a large number of layers was fabricated using the atomic layer deposition (ALD) technique. Experimental dielectric functions for Al:ZnO/ZnO structures are obtained by an ellipsometry technique in the visible and near-infrared spectral ranges. The theoretical modeling of the Al:ZnO/ZnO dielectric permittivity is done using effective medium approximation. A method for analysis of spectroscopic ellipsometry data is demonstrated to extract the optical permittivity for this highly anisotropic nano-layered metamaterial. The results of the ellipsometry analysis show that Al:ZnO/ZnO structures with a 1:9 ALD cycle ratio exhibit hyperbolic dispersion transition change near 1.8more » μm wavelength.« less

Beam Technologies for Integrated Processing

DTIC Science & Technology

1992-03-01

Ohki et al., 1988). Initially, they were used in ion Table 3-3 Ceramic Materials Produced by CVD Coating Chemical Mixture Deposition Temp. (* C ) Method...inner coating , deposited from tungsten hexafluoride, providing strength and creep resistance , and the outer layer, deposited from the chloride, has a (110...1971. Structure and Mechanical Properties of Co - deposited Pyrolytic C -SiC Alloys. Journal of the American Ceramic Society 54:605. Kashu, S., M. Nagase

A novel approach to imaging extinct seafloor massive sulphides (eSMS) by using ocean bottom seismometer data from the Blue Mining project

NASA Astrophysics Data System (ADS)

Gil, A.; Chidlow, K. L.; Vardy, M. E.; Bialas, J.; Schroeder, H.; Stobbs, I. J.; Gehrmann, R. A. S.; North, L. J.; Minshull, T. A.; Petersen, S.; Murton, B. J.

2017-12-01

Seafloor massive sulphide (SMS) deposits have generated great interest regarding their formation and composition, since their discovery in 1977. SMS deposits form through hydrothermal circulation and are therefore commonly found near hydrothermal vent sites. The high base (Cu, Zn) and precious metal (Au, Ag) content has interested mining companies, due to their potentially high economic value. Currently, the possibility of mining extinct seafloor massive sulphides (eSMS) deposits has opened a debate about their environmentally and economically sustainable exploitation. A major goal is the rapid exploration and assessment of deposit structure and volume. This is challenging due to their small dimensions (100s m diameter) and typically great water depths (> 3000 mbsl). Here we present a novel approach combining seismic reflection/refraction forward modelling to data acquired from the TAG hydrothermal field (26ºN, Mid-Atlantic Ridge, 3500mbsl) to image deep-water eSMS deposits. In May 2016, the RV METEOR shot 30, short (<10km) MSC profiles across the TAG area. The data were recorded on a dense cluster (<75 m apart) of ocean bottom seismometers (OBS) and were able to image the subsurface of several 300m diameter eSMS deposits. The results show that the eSMS deposits present high velocities (5.4-6.6 km/s) to depths 200m below the seafloor where they are hosted in a 500m thick low-velocity (3.0-3.7 km/s) layer of altered basalt. In contrast to active hydrothermal systems, we see no evidence in the eSMS of a low-velocity anhydrite layer. The velocity-depth models obtained from this innovative method have been combined with other methods to study these eSMS deposits, such as electromagnetics, rocks physics and drilling technics, and the results are shown to concur, yielding information about deposit structure at depth. For example, the high-velocity layer extends deeper than the conductive layer, indicating a deep stock work of low-connectivity sulphides beneath a main ore body of more massive sulphide. These geophysical methods allow a better constraint on the volume of sulphide at typical SMS with implications for the metal budget within oceanic crust. This work was funded by the European Union's `Blue Mining' project, n˚ 604500.

System-based approach for an advanced drug delivery platform

NASA Astrophysics Data System (ADS)

Kulinsky, Lawrence; Xu, Han; Tsai, Han-Kuan A.; Madou, Marc

2006-03-01

Present study is looking at the problem of integrating drug delivery microcapsule, a bio-sensor, and a control mechanism into a biomedical drug delivery system. A wide range of medical practices from cancer therapy to gastroenterological treatments can benefit from such novel bio-system. Drug release in our drug delivery system is achieved by electrochemically actuating an array of polymeric valves on a set of drug reservoirs. The valves are bi-layer structures, made in the shape of a flap hinged on one side to a valve seat, and consisting of thin films of evaporated gold and electrochemically deposited polypyrrole (PPy). These thin PPy(DBS) bi-layer flaps cover access holes of underlying chambers micromachined in a silicon substrate. Chromium and polyimide layers are applied to implement "differential adhesion" to obtain a voltage induced deflection of the bilayer away from the drug reservoir. The Cr is an adhesion-promoting layer, which is used to strongly bind the gold layer down to the substrate, whereas the gold adheres weakly to polyimide. Drug actives (dry or wet) were pre-stored in the chambers and their release is achieved upon the application of a small bias (~ 1V). Negative voltage causes cation adsorption and volume change in PPy film. This translates into the bending of the PPy/Au bi-layer actuator and release of the drug from reservoirs. This design of the drug delivery module is miniaturized to the dimensions of 200μm valve diameter. Galvanostatic and potentiostatic PPy deposition methods were compared, and potentiostatic deposition method yields film of more uniform thickness. PPy deposition experiments with various pyrrole and NaDBS concentrations were also performed. Glucose biosensor based on glucose oxidase (GOx) embedded in the PPy matrix during elechtrochemical deposition was manufactured and successfully tested. Multiple-drug pulsatile release and continuous linear release patterns can be implemented by controlling the operation of an array of valves. Varying amounts of drugs, together with more complex controlling strategies would allow creation of more complex drug delivery patterns.

Layering extraction from subsurface radargrams over Greenland and the Martian NPLD by combining wavelet analysis with Hough transforms

NASA Astrophysics Data System (ADS)

Xiong, Si-Ting; Muller, Jan-Peter

2017-04-01

Extracting lines from an imagery is a solved problem in the field of edge detection. Different to images taken by camera, radargrams are a set of radar echo profiles, which record wave energy reflected by subsurface reflectors, at each location of a radar footprint along the satellite's ground track. The radargrams record where there is a dielectric contrast caused by different deposits, and other subsurface features, such as facies, and internal distributions like porosity and fluids. Among the subsurface features, layering is an important one which reflect the sequence of seasonal or yearly deposits on the ground [1-2]. In the field of image processing, line detection methods, such as the Radon Transform or Hough Transform, are able to extract these subsurface layers from rasterised versions of the echograms. However, due to the attenuation of radar waves whilst propagating through geological media, radargrams sometimes suffer from gradient and high background noise. These attributes of radargrams cause errors in detection when conventional line detection methods are directly applied. In this study, we have developed a continuous wavelet analysis technique to be applied directly to the radar echo profiles in a radargram in order to detect segmented lines, and then a conventional line detection method, such as a Hough transform can be applied to connect these segmented lines. This processing chain is tested by using datasets from a radargram acquired by the Multi-channel Coherent Radar Depth Sounder (MCoRDS) on an airborne platform in Greenland and a radargram acquired by the SHAllow RADar (SHARAD) on board the Mars Reconnaissance Orbiter (MRO) [3] over Martian North Polar Layered Deposits (NPLD). Keywords: Subsurface mapping, Radargram, SHARAD, Greenland, Martian NPLD, Subsurface layering, line detection References: [1] Phillips, R. J., et al. "Mars north polar deposits: Stratigraphy, age, and geodynamical response." Science 320.5880 (2008): 1182-1185. [2] Cutts, James A., and Blake H. Lewis. "Models of climate cycles recorded in Martian polar layered deposits." Icarus 50.2 (1982): 216-244. [3] Plaut J J, Picardi G, Safaeinili A, et al. Subsurface radar sounding of the south polar layered deposits of Mars[J]. science, 2007, 316(5821): 92-95. Acknowledgements: Part of the research leading to these results has received funding from the STFC "MSSL Consolidated Grant" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement No. 607379 as well as from the China Scholarship Council and the UCL Dean of MAPS fund.

Investigations into the impact of various substrates and ZnO ultra thin seed layers prepared by atomic layer deposition on growth of ZnO nanowire array

PubMed Central

2012-01-01

The impact of various substrates and zinc oxide (ZnO) ultra thin seed layers prepared by atomic layer deposition on the geometric morphology of subsequent ZnO nanowire arrays (NWs) fabricated by the hydrothermal method was investigated. The investigated substrates included B-doped ZnO films, indium tin oxide films, single crystal silicon (111), and glass sheets. Scanning electron microscopy and X-ray diffraction measurements revealed that the geometry and aligment of the NWs were controlled by surface topography of the substrates and thickness of the ZnO seed layers, respectively. According to atomic force microscopy data, we suggest that the substrate, fluctuate amplitude and fluctuate frequency of roughness on ZnO seed layers have a great impact on the alignment of the resulting NWs, whereas the influence of the seed layers' texture was negligible. PMID:22759838

Laminated rare earth structure and method of making

DOEpatents

Senor, David J [West Richland, WA; Johnson, Roger N [Richland, WA; Reid, Bruce D [Pasco, WA; Larson, Sandra [Richland, WA

2002-07-30

A laminated structure having two or more layers, wherein at least one layer is a metal substrate and at least one other layer is a coating comprising at least one rare earth element. For structures having more than two layers, the coating and metal substrate layers alternate. In one embodiment of the invention, the structure is a two-layer laminate having a rare earth coating electrospark deposited onto a metal substrate. In another embodiment of the invention, the structure is a three-layer laminate having the rare earth coating electrospark deposited onto a first metal substrate and the coating subsequently abonded to a second metal substrate. The bonding of the coating to the second metal substrate may be accomplished by hot pressing, hot rolling, high deformation rate processing, or combinations thereof. The laminated structure may be used in nuclear components where reactivity control or neutron absorption is desired and in non-nuclear applications such as magnetic and superconducting films.

A stable downward continuation of airborne magnetic data: A case study for mineral prospectivity mapping in Central Iran

NASA Astrophysics Data System (ADS)

Abedi, Maysam; Gholami, Ali; Norouzi, Gholam-Hossain

2013-03-01

Previous studies have shown that a well-known multi-criteria decision making (MCDM) technique called Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE II) to explore porphyry copper deposits can prioritize the ground-based exploratory evidential layers effectively. In this paper, the PROMETHEE II method is applied to airborne geophysical (potassium radiometry and magnetometry) data, geological layers (fault and host rock zones), and various extracted alteration layers from remote sensing images. The central Iranian volcanic-sedimentary belt is chosen for this study. A stable downward continuation method as an inverse problem in the Fourier domain using Tikhonov and edge-preserving regularizations is proposed to enhance magnetic data. Numerical analysis of synthetic models show that the reconstructed magnetic data at the ground surface exhibits significant enhancement compared to the airborne data. The reduced-to-pole (RTP) and the analytic signal filters are applied to the magnetic data to show better maps of the magnetic anomalies. Four remote sensing evidential layers including argillic, phyllic, propylitic and hydroxyl alterations are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images in order to map the altered areas associated with porphyry copper deposits. Principal component analysis (PCA) based on six Enhanced Thematic Mapper Plus (ETM+) images is implemented to map iron oxide layer. The final mineral prospectivity map based on desired geo-data set indicates adequately matching of high potential zones with previous working mines and copper deposits.

Compositional control of continuously graded anode functional layer

NASA Astrophysics Data System (ADS)

McCoppin, J.; Barney, I.; Mukhopadhyay, S.; Miller, R.; Reitz, T.; Young, D.

2012-10-01

In this work, solid oxide fuel cells (SOFC's) are fabricated with linear-compositionally graded anode functional layers (CGAFL) using a computer-controlled compound aerosol deposition (CCAD) system. Cells with different CGAFL thicknesses (30 um and 50 um) are prepared with a continuous compositionally graded interface deposited between the electrolyte and anode support current collecting regions. The compositional profile was characterized using energy dispersive X-ray spectroscopic mapping. An analytical model of the compound aerosol deposition was developed. The model predicted compositional profiles for both samples that closely matched the measured profiles, suggesting that aerosol-based deposition methods are capable of creating functional gradation on length scales suitable for solid oxide fuel cell structures. The electrochemical performances of the two cells are analyzed using electrochemical impedance spectroscopy (EIS).

Biaxially textured articles formed by plastic deformation

DOEpatents

Goyal, Amit

2001-01-01

A method of preparing a biaxially textured article comprises the steps of providing a metal preform, coating or laminating the preform with a metal layer, deforming the layer to a sufficient degree, and rapidly recrystallizing the layer to produce a biaxial texture. A superconducting epitaxial layer may then be deposited on the biaxial texture. In some embodiments the article further comprises buffer layers, electromagnetic devices or electro-optical devices.

Method of depositing buffer layers on biaxially textured metal substrates

DOEpatents

Beach, David B.; Morrell, Jonathan S.; Paranthaman, Mariappan; Chirayil, Thomas; Specht, Eliot D.; Goyal, Amit

2002-08-27

A laminate article comprises a substrate and a biaxially textured (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer layer over the substrate, wherein 0

High quality Ge epilayer on Si (1 0 0) with an ultrathin Si1-x Ge x /Si buffer layer by RPCVD

NASA Astrophysics Data System (ADS)

Chen, Da; Guo, Qinglei; Zhang, Nan; Xu, Anli; Wang, Bei; Li, Ya; Wang, Gang

2017-07-01

The authors report a method to grow high quality strain-relaxed Ge epilayer on a combination of low temperature Ge seed layer and Si1-x Ge x /Si superlattice buffer layer by reduced pressure chemical vapor deposition system without any subsequent annealing treatment. Prior to the growth of high quality Ge epilayer, an ultrathin Si1-x Ge x /Si superlattice buffer layer with the thickness of 50 nm and a 460 nm Ge seed layer were deposited successively at low temperature. Then an 840 nm Ge epilayer was grown at high deposition rate with the surface root-mean-square roughness of 0.707 nm and threading dislocation density of 2.5  ×  106 cm-2, respectively. Detailed investigations of the influence of ultrathin low-temperature Si1-x Ge x /Si superlattice buffer layer on the quality of Ge epilayer were performed, which indicates that the crystalline quality of Ge epilayer can be significantly improved by enhancing the Ge concentration of Si1-x Ge x /Si superlattice buffer layer.

Atomic-Layer-Deposited Transparent Electrodes for Silicon Heterojunction Solar Cells

DOE PAGES

Demaurex, Benedicte; Seif, Johannes P.; Smit, Sjoerd; ...

2014-11-01

We examine damage-free transparent-electrode deposition to fabricate high-efficiency amorphous silicon/crystalline silicon heterojunction solar cells. Such solar cells usually feature sputtered transparent electrodes, the deposition of which may damage the layers underneath. Using atomic layer deposition, we insert thin protective films between the amorphous silicon layers and sputtered contacts and investigate their effect on device operation. We find that a 20-nm-thick protective layer suffices to preserve, unchanged, the amorphous silicon layers beneath. Insertion of such protective atomic-layer-deposited layers yields slightly higher internal voltages at low carrier injection levels. However, we identify the presence of a silicon oxide layer, formed during processing,more » between the amorphous silicon and the atomic-layer-deposited transparent electrode that acts as a barrier, impeding hole and electron collection.« less

Architectures and criteria for the design of high efficiency organic photovoltaic cells

DOEpatents

Rand, Barry; Forrest, Stephen R; Pendergrast Burk, Diane

2015-03-31

A method for fabricating an organic photovoltaic cell includes providing a first electrode; depositing a series of at least seven layers onto the first electrode, each layer consisting essentially of a different organic semiconductor material, the organic semiconductor material of at least an intermediate layer of the sequence being a photoconductive material; and depositing a second electrode onto the sequence of at least seven layers. One of the first electrode and the second electrode is an anode and the other is a cathode. The organic semiconductor materials of the series of at least seven layers are arranged to provide a sequence of decreasing lowest unoccupied molecular orbitals (LUMOs) and a sequence of decreasing highest occupied molecular orbitals (HOMOs) across the series from the anode to the cathode.

CuGaS₂ and CuGaS₂-ZnS Porous Layers from Solution-Processed Nanocrystals.

PubMed

Berestok, Taisiia; Guardia, Pablo; Estradé, Sònia; Llorca, Jordi; Peiró, Francesca; Cabot, Andreu; Brock, Stephanie L

2018-04-05

The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS₂ (CGS) and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs). We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS-ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs.

Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

DOEpatents

Wu, X.; Coutts, T.J.; Sheldon, P.; Rose, D.H.

1999-07-13

A photovoltaic device is disclosed having a substrate, a layer of Cd[sub 2]SnO[sub 4] disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd[sub 2]SnO[sub 4], and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd[sub 2]SnO[sub 4] layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd[sub 2]SnO[sub 4], and depositing an electrically conductive film onto the thin film of semiconductor materials. 10 figs.

Geological identification of historical tsunamis in the Gulf of Corinth, Central Greece

NASA Astrophysics Data System (ADS)

Kortekaas, S.; Papadopoulos, G. A.; Ganas, A.; Cundy, A. B.; Diakantoni, A.

2011-07-01

Geological identification of tsunami deposits is important for tsunami hazard studies, especially in areas where the historical data set is limited or absent. Evidence left by historical tsunamis in the coastal sedimentary record of the Gulf of Corinth was investigated by trenching and coring in Kirra on the north coast and Aliki on the south coast. The Gulf of Corinth has a documented tsunami history dating back to the 4th century BC. Comparison of the historical records and the results of stratigraphical, sedimentological and foraminiferal analyses show that extreme coastal flooding events are detectable in the coastal sequences. The geological record from Kirra shows four sand layers deposited by high-energy marine flooding events. The deposits identified show many similarities with tsunami deposits described elsewhere. The lower sand deposit (layer 4) was radiocarbon dated to 3020-2820 BC. Assuming an average sedimentation rate of 2.6 cm (100 yr)-1, the ages of the other three sand layers were estimated by extrapolation to the time windows 1200-1000 BC, AD 500-600 and AD 1400-1500. There are no historical tsunamis which correlate with layers 2 and 3. However, layer 1 may represent the major AD 1402 tsunami. Sand dykes penetrating from layer 1 into the overlying silts suggest soil liquefaction during an earthquake event, possibly the 1 August 1870 one. At Aliki, no clear stratigraphical evidence of tsunami flooding was found, but results from foraminiferal and dating analyses show that a sand layer was deposited about 180 years ago from a marine flooding event. This layer may be associated with the historical tsunami of 23 August 1817, which caused widespread destruction in the Aegion area. The work presented here supports the idea that geological methods can be used to extend tsunami history far beyond the historical record. Although the tsunami database obtained will be incomplete and biased towards larger events, it will still be useful for extreme event statistical approaches.

Evolution of zirconyl-stearate Langmuir monolayers and the synthesized ZrO2 thin films with pH

NASA Astrophysics Data System (ADS)

Choudhary, Raveena; Sharma, Rajni; Brar, Loveleen K.

2018-04-01

ZrO2 thin films have a wide range of applications ranging from photonics, antireflection coatings, and resistive oxygen gas sensors, as a gate dielectric and in high temperature fuel cells. We have used the deposition of zirconyl stearate monolayers followed by their oxidation as a method for the synthesis of zirconium oxide thin films. The zirconyl stearate films have been studied and deposited for first time to the best of our knowledge. The Langmuir monolayers are studied using pressure-Area (π-A) isotherms and oscillatory barrier method. The morphology of the films for limited number of layers was studied with FE-SEM to determine the effect of pH on the final ZrO2 film. The 200 layer deposition films show pure monoclinic phase. The films have a band gap ˜6.0eV with a strong PL emission peak is at 490 nm and a weak peak is at 423 nm. So the films formed by this deposition method are suitable for luminescent applications

Method for materials deposition by ablation transfer processing

DOEpatents

Weiner, Kurt H.

1996-01-01

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

Self-assembled metal nano-multilayered film prepared by co-sputtering method

NASA Astrophysics Data System (ADS)

Xie, Tianle; Fu, Licai; Qin, Wen; Zhu, Jiajun; Yang, Wulin; Li, Deyi; Zhou, Lingping

2018-03-01

Nano-multilayered film is usually prepared by the arrangement deposition of different materials. In this paper, a self-assembled nano-multilayered film was deposited by simultaneous sputtering of Cu and W. The Cu/W nano-multilayered film was accumulated by W-rich layer and Cu-rich layer. Smooth interfaces with consecutive composition variation and semi-coherent even coherent relationship were identified, indicating that a spinodal-like structure with a modulation wavelength of about 20 nm formed during co-deposition process. The participation of diffusion barrier element, such as W, is believed the essential to obtain the nano-multilayered structure besides the technological parameters.

Atomic layer deposition of titanium oxide films on As-synthesized magnetic Ni particles: Magnetic and safety properties

NASA Astrophysics Data System (ADS)

Uudeküll, Peep; Kozlova, Jekaterina; Mändar, Hugo; Link, Joosep; Sihtmäe, Mariliis; Käosaar, Sandra; Blinova, Irina; Kasemets, Kaja; Kahru, Anne; Stern, Raivo; Tätte, Tanel; Kukli, Kaupo; Tamm, Aile

2017-05-01

Spherical nickel particles with size in the range of 100-400 nm were synthesized by non-aqueous liquid phase benzyl alcohol method. Being developed for magnetically guided biomedical applications, the particles were coated by conformal and antimicrobial thin titanium oxide films by atomic layer deposition. The particles retained their size and crystal structure after the deposition of oxide films. The sensitivity of the coated particles to external magnetic fields was increased compared to that of the uncoated powder. Preliminary toxicological investigations on microbial cells and small aquatic crustaceans revealed non-toxic nature of the synthesized particles.

Method of depositing a coating on Si-based ceramic composites

NASA Technical Reports Server (NTRS)

Wang, Hongyu (Inventor); Lau, Yuk-Chiu (Inventor); Spitsberg, Irene (Inventor); Henry, Arnold T. (Inventor)

2004-01-01

A process of depositing a coating system suitable for use as an environmental barrier coating on various substrate materials, particularly those containing silicon and intended for high temperature applications such as the hostile thermal environment of a gas turbine engine. The process comprises depositing a first coating layer containing mullite, and preferably a second coating layer of an alkaline earth aluminosilicate, such as barium-strontium-aluminosilicate (BSAS), by thermal spraying while maintaining the substrate at a temperature of 800.degree. C. or less, preferably 500.degree. C. or less, by which a substantially crack-free coating system is produced with desirable mechanical integrity.

Titanium dioxide fine structures by RF magnetron sputter method deposited on an electron-beam resist mask

NASA Astrophysics Data System (ADS)

Hashiba, Hideomi; Miyazaki, Yuta; Matsushita, Sachiko

2013-09-01

Titanium dioxide (TiO2) has been draw attention for wide range of applications from photonic crystals for visible light range by its catalytic characteristics to tera-hertz range by its high refractive index. We present an experimental study of fabrication of fine structures of TiO2 with a ZEP electron beam resist mask followed by Ti sputter deposition techniques. A TiO2 thin layer of 150 nm thick was grown on an FTO glass substrate with a fine patterned ZEP resist mask by a conventional RF magnetron sputter method with Ti target. The deposition was carried out with argon-oxygen gases at a pressure of 5.0 x 10 -1 Pa in a chamber. During the deposition, ratio of Ar-O2 gas was kept to the ratio of 2:1 and the deposition ratio was around 0.5 Å/s to ensure enough oxygen to form TiO2 and low temperature to avoid deformation of fine pattern of the ZPU resist mask. Deposited TiO2 layers are white-transparent, amorphous, and those roughnesses are around 7 nm. Fabricated TiO2 PCs have wider TiO2 slabs of 112 nm width leaving periodic 410 x 410 nm2 air gaps. We also studied transformation of TiO2 layers and TiO2 fine structures by baking at 500 °C. XRD measurement for TiO2 shows that the amorphous TiO2 transforms to rutile and anatase forms by the baking while keeping the same profile of the fine structures. Our fabrication method can be one of a promising technique to optic devices on researches and industrial area.

Optimal control of build height utilizing optical profilometry in cold spray deposits

NASA Astrophysics Data System (ADS)

Chakraborty, Abhijit; Shishkin, Sergey; Birnkrant, Michael J.

2017-04-01

Part-to-part variability and poor part quality due to failure to maintain geometric specifications pose a challenge for adopting Additive Manufacturing (AM) as a viable manufacturing process. In recent years, In-process Monitoring and Control (InPMC) has received a lot of attention as an approach to overcome these obstacles. The ability to sense geometry of the deposited layers accurately enables effective process monitoring and control of AM application. This paper demonstrates an application of geometry sensing technique for the coating deposition Cold Spray process, where solid powders are accelerated through a nozzle, collides with the substrate and adheres to it. Often the deposited surface has shape irregularities. This paper proposes an approach to suppress the iregularities by controlling the deposition height. An analytical control-oriented model is developed that expresses the resulting height of deposit as an integral function of nozzle velocity and angle. In order to obtain height information at each layer, a Micro-Epsilon laser line scanner was used for surface profiling after each deposition. This surface profile information, specifically the layer height, was then fed back to an optimal control algorithm which manipulated the nozzle speed to control the layer height to a pre specified height. While the problem is heavily nonlinear, we were able to transform it into equivalent Optimal Control problem linear w.r.t. input. That enabled development of two solution methods: one is fast and approximate, while another is more accurate but still efficient.

Atomic layer epitaxy of hematite on indium tin oxide for application in solar energy conversion

DOEpatents

Martinson, Alex B.; Riha, Shannon; Guo, Peijun; Emery, Jonathan D.

2016-07-12

A method to provide an article of manufacture of iron oxide on indium tin oxide for solar energy conversion. An atomic layer epitaxy method is used to deposit an uncommon bixbytite-phase iron (III) oxide (.beta.-Fe.sub.2O.sub.3) which is deposited at low temperatures to provide 99% phase pure .beta.-Fe.sub.2O.sub.3 thin films on indium tin oxide. Subsequent annealing produces pure .alpha.-Fe.sub.2O.sub.3 with well-defined epitaxy via a topotactic transition. These highly crystalline films in the ultra thin film limit enable high efficiency photoelectrochemical chemical water splitting.

Simple method to enhance positive bias stress stability of In-Ga-Zn-O thin-film transistors using a vertically graded oxygen-vacancy active layer.

PubMed

Park, Ji Hoon; Kim, Yeong-Gyu; Yoon, Seokhyun; Hong, Seonghwan; Kim, Hyun Jae

2014-12-10

We proposed a simple method to deposit a vertically graded oxygen-vacancy active layer (VGA) to enhance the positive bias stress (PBS) stability of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). We deposited a-IGZO films by sputtering (target composition; In2O3:Ga2O3:ZnO = 1:1:1 mol %), and the oxygen partial pressure was varied during deposition so that the front channel of the TFTs was fabricated with low oxygen partial pressure and the back channel with high oxygen partial pressure. Using this method, we were able to control the oxygen vacancy concentration of the active layer so that it varied with depth. As a result, the turn-on voltage shift following a 10 000 s PBS of optimized VGA TFT was drastically improved from 12.0 to 5.6 V compared with a conventional a-IGZO TFT, without a significant decrease in the field effect mobility. These results came from the self-passivation effect and decrease in oxygen-vacancy-related trap sites of the VGA TFTs.

Methods of producing free-standing semiconductors using sacrificial buffer layers and recyclable substrates

DOEpatents

Ptak, Aaron Joseph; Lin, Yong; Norman, Andrew; Alberi, Kirstin

2015-05-26

A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a spinel substrate using a sacrificial buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The sacrificial buffer material and semiconductor materials may be deposited using lattice-matching epitaxy or coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The sacrificial buffer layer may be dissolved using an epitaxial liftoff technique in order to separate the semiconductor device from the spinel substrate, and the spinel substrate may be reused in the subsequent fabrication of other semiconductor devices. The low-defect density semiconductor materials produced using this method result in the enhanced performance of the semiconductor devices that incorporate the semiconductor materials.

Optical in situ monitoring of plasma-enhanced atomic layer deposition process

NASA Astrophysics Data System (ADS)

Zeeshan Arshad, Muhammad; Jo, Kyung Jae; Kim, Hyun Gi; Jeen Hong, Sang

2018-06-01

An optical in situ process monitoring method for the early detection of anomalies in plasma process equipment is presented. Cyclic process steps of precursor treatment and plasma reaction for the deposition of an angstrom-scale film increase their complexity to ensure the process quality. However, a small deviation in process parameters, for instance, gas flow rate, process temperature, or RF power, may jeopardize the deposited film quality. As a test vehicle for the process monitoring, we have investigated the aluminum-oxide (Al2O3) encapsulation process in plasma-enhanced atomic layer deposition (PEALD) to form a moisture and oxygen diffusion barrier in organic-light emitting diodes (OLEDs). By optical in situ monitoring, we successfully identified the reduction in oxygen flow rates in the reaction steps, which resulted in a 2.67 times increase in the water vapor transmission ratio (WVTR) of the deposited Al2O3 films. Therefore, we are convinced that the suggested in situ monitoring method is useful for the detection of process shifts or drifts that adversely affect PEALD film quality.

Thin film capillary process and apparatus

DOEpatents

Yu, Conrad M.

2003-11-18

Method and system of forming microfluidic capillaries in a variety of substrate materials. A first layer of a material such as silicon dioxide is applied to a channel etched in substrate. A second, sacrificial layer of a material such as a polymer is deposited on the first layer. A third layer which may be of the same material as the first layer is placed on the second layer. The sacrificial layer is removed to form a smooth walled capillary in the substrate.

Chemical solution seed layer for rabits tapes

DOEpatents

Goyal, Amit; Paranthaman, Mariappan; Wee, Sung-Hun

2014-06-10

A method for making a superconducting article includes the steps of providing a biaxially textured substrate. A seed layer is then deposited. The seed layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different rare earth or transition metal cations. A superconductor layer is grown epitaxially such that the superconductor layer is supported by the seed layer.

Investigation on single walled carbon nanotube thin films deposited by Langmuir Blodgett method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vishalli,, E-mail: vishalli-2008@yahoo.com; Dharamvir, Keya; Kaur, Ramneek

2015-05-15

Langmuir Blodgett is a technique to deposit a homogeneous film with a fine control over thickness and molecular organization. Thin films of functionalized SWCNTs have been prepared by Langmuir Blodgett method. The good surface spreading properties of SWCNTs at air/water interface are indicated by surface pressure-area isotherm and the monolayer formed on water surface is transferred onto the quartz substrate by vertical dipping. A multilayer film is thus obtained in a layer by layer manner. The film is characterized by Atomic Force Microscope (AFM), UV-Vis-NIR spectroscopy and FTIR.AFM shows the surface morphology of the deposited film. UV-Vis-NIR spectroscopy shows themore » characteristic peaks of semiconducting SWCNTs. The uniformity of LB film can be used further in understanding the optical and electrical behavior of these materials.« less

Microchannel plate detector and methods for their fabrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elam, Jeffrey W.; Mane, Anil U.; Peng, Qing

A multi-component tunable resistive coating and methods of depositing the coating on the surfaces of a microchannel plate (MCP) detector. The resistive coating composed of a plurality of alternating layers of a metal oxide resistive component layer and a conductive component layer composed of at least one of a metal, a metal nitride and a metal sulfide. The coating may further include an emissive layer configured to produce a secondary electron emission in response to a particle interacting with the MCP and a neutron-absorbing layer configured to respond to a neutron interacting with the MCP.

Impacts of oxidants in atomic layer deposition method on Al2O3/GaN interface properties

NASA Astrophysics Data System (ADS)

Taoka, Noriyuki; Kubo, Toshiharu; Yamada, Toshikazu; Egawa, Takashi; Shimizu, Mitsuaki

2018-01-01

The electrical interface properties of GaN metal-oxide-semiconductor (MOS) capacitors with an Al2O3 gate insulator formed by atomic layer deposition method using three kinds of oxidants were investigated by the capacitance-voltage technique, Terman method, and conductance method. We found that O3 and the alternate supply of H2O and O3 (AS-HO) are effective for reducing the interface trap density (D it) at the energy range of 0.15 to 0.30 eV taking from the conduction band minimum. On the other hand, we found that surface potential fluctuation (σs) induced by interface charges for the AS-HO oxidant is much larger than that for a Si MOS capacitor with a SiO2 layer formed by chemical vapor deposition despite the small D it values for the AS-HO oxidant compared with the Si MOS capacitor. This means that the total charged center density including the fixed charge density, charged slow trap density, and charged interface trap density for the GaN MOS capacitor is higher than that for the Si MOS capacitor. Therefore, σs has to be reduced to improve the performances and reliability of GaN devices with the Al2O3/GaN interfaces.

Translocation of the retinal pigment epithelium and formation of sub-retinal pigment epithelium deposit induced by subretinal deposit

PubMed Central

Zhao, Lian; Wang, Zhenfang; Liu, Yun; Song, Ying; Li, Yiwen; Laties, Alan M.

2007-01-01

Purpose A cardinal pathological feature of age-related macular degeneration (AMD) is the deposition of extracellular material between the retinal pigment epithelium (RPE) and Bruch's membrane, pathologically described as sub-RPE deposits. Both the presence and local organization of these deposits contribute to the clinical manifestations of AMD, including localized deposits clinically recognized as drusen. The biogenesis of sub-RPE deposits remains elusive. This work explores the pathological processes of sub-RPE deposit formation. Methods Matrigel was injected to the subretinal space of rats to create an amorphous deposit. Tissue sections were examined by light or confocal microscopy. Results In the presence of the subretinal deposit of Matrigel, RPE cells leave Bruch's membrane to migrate toward photoreceptors and then form a new layer between the deposit and photoreceptors, resulting in RPE translocation. The new RPE layer displaces the deposit to the sub-RPE location and therefore it becomes a sub-RPE deposit. The RPE mobilization requires the presence of photoreceptors. Bruch's membrane devoid of RPE attachment becomes vulnerable to invasion by new blood vessels from the choroid. Conclusions Our work supports a novel model of sub-RPE deposit formation in which excessive material first accumulates in the subretinal space, disrupting the physical contact between RPE cells and photoreceptors. To restore the contact, RPE cells migrate toward photoreceptors and form a new layer. The subretinal material is consequently displaced to the sub-RPE location and becomes sub-RPE deposit. Our data also provide evidence that the presence of sub-RPE deposit is sufficient to induce choroidal neovascularization to penetrate Bruch's membrane. PMID:17615538

Technique for forming ITO films with a controlled refractive index

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markov, L. K., E-mail: l.markov@mail.ioffe.ru; Smirnova, I. P.; Pavluchenko, A. S.

2016-07-15

A new method for fabricating transparent conducting coatings based on indium-tin oxide (ITO) with a controlled refractive index is proposed. This method implies the successive deposition of material by electron-beam evaporation and magnetron sputtering. Sputtered coatings with different densities (and, correspondingly, different refractive indices) can be obtained by varying the ratio of the mass fractions of material deposited by different methods. As an example, films with effective refractive indices of 1.2, 1.4, and 1.7 in the wavelength range of 440–460 nm are fabricated. Two-layer ITO coatings with controlled refractive indices of the layers are also formed by the proposed method.more » Thus, multilayer transparent conducting coatings with desired optical parameters can be produced.« less

Fabrication of a transparent conducting electrode based on graphene/silver nanowires via layer-by-layer method for organic photovoltaic devices.

PubMed

Tugba Camic, B; Oytun, Faruk; Hasan Aslan, M; Jeong Shin, Hee; Choi, Hyosung; Basarir, Fevzihan

2017-11-01

A solution-processed transparent conducting electrode was fabricated via layer-by-layer (LBL) deposition of graphene oxide (GO) and silver nanowires (Ag NWs). First, graphite was oxidized with a modified Hummer's method to obtain negatively-charged GO sheets, and Ag NWs were functionalized with cysteamine hydrochloride to acquire positively-charged silver nanowires. Oppositely-charged GO and Ag NWs were then sequentially coated on a 3-aminopropyltriethoxysilane modified glass substrate via LBL deposition, which provided highly controllable thin films in terms of optical transmittance and sheet resistance. Next, the reduction of GO sheets was performed to improve the electrical conductivity of the multilayer films. The resulting GO/Ag NWs multilayer was characterized by a UV-Vis spectrometer, field emission scanning electron microscope (FE-SEM), optical microscope (OM) and sheet resistance using a four-point probe method. The best result was achieved with a 2-bilayer film, resulting in a sheet resistance of 6.5Ω sq -1 with an optical transmittance of 78.2% at 550nm, which values are comparable to those of commercial ITO electrodes. The device based on a 2-bilayer hybrid film exhibited the highest device efficiency of 1.30% among the devices with different number of graphene/Ag NW LBL depositions. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnetic domain observation of FeCo thin films fabricated by alternate monoatomic layer deposition

NASA Astrophysics Data System (ADS)

Ohtsuki, T.; Kojima, T.; Kotsugi, M.; Ohkochi, T.; Mizuguchi, M.; Takanashi, K.

2014-01-01

FeCo thin films are fabricated by alternate monoatomic layer deposition method on a Cu3Au buffer layer, which in-plane lattice constant is very close to the predicted value to obtain a large magnetic anisotropy constant. The variation of the in-plane lattice constant during the deposition process is investigated by reflection high-energy electron diffraction. The magnetic domain images are also observed by a photoelectron emission microscope in order to microscopically understand the magnetic structure. As a result, element-specific magnetic domain images show that Fe and Co magnetic moments align parallel. A series of images obtained with various azimuth reveal that the FeCo thin films show fourfold in-plane magnetic anisotropy along ⟨110⟩ direction, and that the magnetic domain structure is composed only of 90∘ wall.

Ta2O5/ Al2O3/ SiO2 - antireflective coating for non-planar optical surfaces by atomic layer deposition

NASA Astrophysics Data System (ADS)

Pfeiffer, K.; Schulz, U.; Tünnermann, A.; Szeghalmi, A.

2017-02-01

Antireflective coatings are essential to improve transmittance of optical elements. Most research and development of AR coatings has been reported on a wide variety of plane optical surfaces; however, antireflection is also necessary on nonplanar optical surfaces. Physical vapor deposition (PVD), a common method for optical coatings, often results in thickness gradients on strongly curved surfaces, leading to a failure of the desired optical function. In this work, optical thin films of tantalum pentoxide, aluminum oxide and silicon dioxide were prepared by atomic layer deposition (ALD), which is based on self-limiting surface reactions. The results demonstrate that ALD optical layers can be deposited on both vertical and horizontal substrate surfaces with uniform thicknesses and the same optical properties. A Ta2O5/Al2O3/ SiO2 multilayer AR coating (400-700 nm) was successfully applied to a curved aspheric glass lens with a diameter of 50 mm and a center thickness of 25 mm.

Layered reactive particles with controlled geometries, energies, and reactivities, and methods for making the same

DOEpatents

Fritz, Gregory M.; Weihs, Timothy P.; Grzyb, Justin A.

2016-07-05

An energetic composite having a plurality of reactive particles each having a reactive multilayer construction formed by successively depositing reactive layers on a rod-shaped substrate having a longitudinal axis, dividing the reactive-layer-deposited rod-shaped substrate into a plurality of substantially uniform longitudinal segments, and removing the rod-shaped substrate from the longitudinal segments, so that the reactive particles have a controlled, substantially uniform, cylindrically curved or otherwise rod-contoured geometry which facilitates handling and improves its packing fraction, while the reactant multilayer construction controls the stability, reactivity and energy density of the energetic composite.

Layered reactive particles with controlled geometries, energies, and reactivities, and methods for making the same

DOEpatents

Fritz, Gregory M; Knepper, Robert Allen; Weihs, Timothy P; Gash, Alexander E; Sze, John S

2013-04-30

An energetic composite having a plurality of reactive particles each having a reactive multilayer construction formed by successively depositing reactive layers on a rod-shaped substrate having a longitudinal axis, dividing the reactive-layer-deposited rod-shaped substrate into a plurality of substantially uniform longitudinal segments, and removing the rod-shaped substrate from the longitudinal segments, so that the reactive particles have a controlled, substantially uniform, cylindrically curved or otherwise rod-contoured geometry which facilitates handling and improves its packing fraction, while the reactant multilayer construction controls the stability, reactivity and energy density of the energetic composite.

Fabrication of CIS Absorber Layers with Different Thicknesses Using A Non-Vacuum Spray Coating Method.

PubMed

Diao, Chien-Chen; Kuo, Hsin-Hui; Tzou, Wen-Cheng; Chen, Yen-Lin; Yang, Cheng-Fu

2014-01-03

In this study, a new thin-film deposition process, spray coating method (SPM), was investigated to deposit the high-densified CuInSe₂ absorber layers. The spray coating method developed in this study was a non-vacuum process, based on dispersed nano-scale CuInSe₂ precursor and could offer a simple, inexpensive, and alternative formation technology for CuInSe₂ absorber layers. After spraying on Mo/glass substrates, the CuInSe₂ thin films were annealed at 550 °C by changing the annealing time from 5 min to 30 min in a selenization furnace, using N₂ as atmosphere. When the CuInSe₂ thin films were annealed, without extra Se or H₂Se gas used as the compensation source during the annealing process. The aim of this project was to investigate the influence of annealing time on the densification and crystallization of the CuInSe₂ absorber layers to optimize the quality for cost effective solar cell production. The thickness of the CuInSe₂ absorber layers could be controlled as the volume of used dispersed CuInSe₂-isopropyl alcohol solution was controlled. In this work, X-ray diffraction patterns, field emission scanning electron microscopy, and Hall parameter measurements were performed in order to verify the quality of the CuInSe₂ absorber layers obtained by the Spray Coating Method.

Characteristics of layered tin disulfide deposited by atomic layer deposition with H2S annealing

NASA Astrophysics Data System (ADS)

Lee, Seungjin; Shin, Seokyoon; Ham, Giyul; Lee, Juhyun; Choi, Hyeongsu; Park, Hyunwoo; Jeon, Hyeongtag

2017-04-01

Tin disulfide (SnS2) has attracted much attention as a two-dimensional (2D) material. A high-quality, low-temperature process for producing 2D materials is required for future electronic devices. Here, we investigate tin disulfide (SnS2) layers deposited via atomic layer deposition (ALD) using tetrakis(dimethylamino)tin (TDMASn) as a Sn precursor and H2S gas as a sulfur source at low temperature (150° C). The crystallinity of SnS2 was improved by H2S gas annealing. We carried out H2S gas annealing at various conditions (250° C, 300° C, 350° C, and using a three-step method). Angle-resolved X-ray photoelectron spectroscopy (ARXPS) results revealed the valence state corresponding to Sn4+ and S2- in the SnS2 annealed with H2S gas. The SnS2 annealed with H2S gas had a hexagonal structure, as measured via X-ray diffraction (XRD) and the clearly out-of-plane (A1g) mode in Raman spectroscopy. The crystallinity of SnS2 was improved after H2S annealing and was confirmed using the XRD full-width at half-maximum (FWHM). In addition, high-resolution transmission electron microscopy (HR-TEM) images indicated a clear layered structure.

Method of making macrocrystalline or single crystal semiconductor material

NASA Technical Reports Server (NTRS)

Shlichta, P. J. (Inventor); Holliday, R. J. (Inventor)

1986-01-01

A macrocrystalline or single crystal semiconductive material is formed from a primary substrate including a single crystal or several very large crystals of a relatively low melting material. This primary substrate is deposited on a base such as steel or ceramic, and it may be formed from such metals as zinc, cadmium, germanium, aluminum, tin, lead, copper, brass, magnesium silicide, or magnesium stannide. These materials generally have a melting point below about 1000 C and form on the base crystals the size of fingernails or greater. The primary substrate has an epitaxial relationship with a subsequently applied layer of material, and because of this epitaxial relationship, the material deposited on the primary substrate will have essentially the same crystal size as the crystals in the primary substrate. If required, successive layers are formed, each of a material which has an epitaxial relationship with the previously deposited layer, until a layer is formed which has an epitaxial relationship with the semiconductive material. This layer is referred to as the epitaxial substrate, and its crystals serve as sites for the growth of large crystals of semiconductive material. The primary substrate is passivated to remove or otherwise convert it into a stable or nonreactive state prior to deposition of the seconductive material.

Method for growing low defect, high purity crystalline layers utilizing lateral overgrowth of a patterned mask

NASA Technical Reports Server (NTRS)

Morrison, Andrew D. (Inventor); Daud, Taher (Inventor)

1986-01-01

A method for growing a high purity, low defect layer of semiconductor is described. This method involves depositing a patterned mask of a material impervious to impurities of the semiconductor on a surface of a blank. When a layer of semiconductor is grown on the mask, the semiconductor will first grow from the surface portions exposed by the openings in the mask and will bridge the connecting portions of the mask to form a continuous layer having improved purity, since only the portions overlying the openings are exposed to defects and impurities. The process can be iterated and the mask translated to further improve the quality of grown layers.

Method utilizing laser-processing for the growth of epitaxial p-n junctions

DOEpatents

Young, R.T.; Narayan, J.; Wood, R.F.

1979-11-23

This invention is a new method for the formation of epitaxial p-n junctions in silicon. The method is relatively simple, rapid, and reliable. It produces doped epitaxial layers which are of well-controlled thickness and whose electrical properties are satisfactory. An illustrative form of the method comprises co-depositing a selected dopant and amorphous silicon on a crystalline silicon substrate to form a doped layer of amorphous silicon thereon. This layer then is irradiated with at least one laser pulse to generate a melt front which moves through the layer, into the silicon body to a depth effecting melting of virginal silicon, and back to the surface of the layer. The method may be conducted with dopants (e.g., boron and phosphorus) whose distribution coefficients approximate unity.

Influence of TiCl4 post-treatment condition on TiO2 electrode for enhancement photovoltaic efficiency of dye-sensitized solar cells.

PubMed

Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

2014-10-01

Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cells (DSSCs) technology. TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells. In this work, the effect of TiCl4 post-treatment on the TiO2 electrode is proposed and compared to the untreated film. A TiO2 passivating layer was deposited on FTO glass by RF magnetron sputtering. The TiO2 sol prepared sol-gel method, nanoporous TiO2 upper layer was deposited by screen printing method on the passivating layer. TiCl4 post-treatment was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Crystalline structure was adjusted by various TiCl4 concentration and dipping time: 20 mM-150 mM and 30 min-120 min. The conversion efficiency was measured by solar simulator (100 mW/cm2). The dye-sensitized solar cell using TiCl4 post-treatment was measured the maximum conversion efficiency of 5.04% due to electron transport effectively. As a result, the DSSCs based on TiCl4 post-treatment showed better photovoltaic performance than cells made purely of TiO2 nanoparticles. The relative DSSCs devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency.

Fabrication of PVDF-based blend membrane with a thin hydrophilic deposition layer and a network structure supporting layer via the thermally induced phase separation followed by non-solvent induced phase separation process

NASA Astrophysics Data System (ADS)

Wu, Zhiguo; Cui, Zhenyu; Li, Tianyu; Qin, Shuhao; He, Benqiao; Han, Na; Li, Jianxin

2017-10-01

A simple strategy of thermally induced phase separation followed by non-solvent induced phase separation (TIPS-NIPS) is reported to fabricate poly (vinylidene fluoride) (PVDF)-based blend membrane. The dissolved poly (styrene-co-maleic anhydride) (SMA) in diluent prevents the crystallization of PVDF during the cooling process and deposites on the established PVDF matrix in the later extraction. Compared with traditional coating technique, this one-step TIPS-NIPS method can not only fabricate a supporting layer with an interconnected network structure even via solid-liquid phase separation of TIPS, but also form a uniform SMA skin layer approximately as thin as 200 nm via surface deposition of NIPS. Besides the better hydrophilicity, what's interesting is that the BSA rejection ratio increases from 48% to 94% with the increase of SMA, which indicates that the separation performance has improved. This strategy can be conveniently extended to the creation of firmly thin layer, surface functionalization and structure controllability of the membrane.

Niobium boride layers deposition on the surface AISI D2 steel by a duplex treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kon, O., E-mail: okon42@htotmail.com; Pazarlioglu, S.; Sen, S.

2015-03-30

In this paper, we investigated the possibility of deposition of niobium boride layers on the surface of AISI D2 steel by a duplex treatment. At the first step of duplex treatment, boronizing was performed on AISI D2 steel samples at 1000{sup o}C for 2h and then pre-boronized samples niobized at 850°C, 900°C and 950°C using thermo-reactive deposition method for 1–4 h. The presence of the niobium boride layers such as NbB, NbB{sub 2} and Nb{sub 3}B{sub 4} and also iron boride phases such as FeB, Fe{sub 2}B were examined by X-ray diffraction analysis. Scanning electron microscope (SEM) and micro-hardness measurementsmore » were realized. Experimental studies showed that the depth of the coating layers increased with increasing temperature and times and also ranged from 0.42 µm to 2.43 µm, depending on treatment time and temperature. The hardness of the niobium boride layer was 2620±180 HV{sub 0.005}.« less

Cobalt disilicide contacts to silicon-germanium alloys

NASA Astrophysics Data System (ADS)

Goeller, Peter Thomas

This dissertation investigated the structure and stability of thin (18--45 nm) cobalt disilicide films, electron beam evaporated onto strained and relaxed Si1--xGex/Si(001) alloy layers. The aim of these investigations was to develop a means of growing smooth, continuous, epitaxial and thermally stable CoSi2 films suitable for use as contacts in SiGe device technology. Previous research on the reaction of Co metal with SiGe alloys has indicated a number of problems, such as film islanding, formation of polycrystalline silicide films, Ge segregation and poor thermal stability. In the present work, we studied the scientific issues underlying these phenomena with a variety of experimental techniques. Our initial studies comparing direct deposition of Co versus co-deposition of Co and Si indicated that co-deposition resulted in CoSi2 formation at much lower temperatures (500°C) than with the direct deposition method (700°C). Furthermore, the co-deposited films were epitaxial to the SiGe layer, whereas the direct deposited films were polycrystalline. Both methods resulting in increasing islanding of the films with increasing annealing temperature. The issues underlying the islanding of the co-deposited films were investigated with an in situ XAFS investigation of the Co/SiGe interface using monolayers of Co. It was determined that Co preferentially bonds with Si atoms as the annealing temperature is increased, leading to segregation of Ge at the interface and faceting of the silicide. A modified template method of silicide growth was devised, in which a sacrificial Si layer was deposited onto the SiGe surface before the CoSi2 template was grown. This growth method was shown to result in smooth, epitaxial and thermally stable films of CoSi2 on Si0.80Ge0.20 alloys. A thickness effect was observed for the direct deposition of Co on SiGe alloys, in which Co layers do not completely convert to CoSi2 until thicknesses greater than 35 nm are deposited. A thermodynamic model was developed, based on the Gibbs free energy change of the CoSi → CoSi2 transition, which indicated that the thickness effect was driven by the presence of Ge in the reaction zone. Finally, the Ge segregation phenomenon accompanying the direct reaction of Co on both strained and relaxed Si0.80Ge0.20 alloys was investigated. It was determined using XRD and EDS in the STEM microscope that Ge segregation on strained SiGe takes the form of Ge-enriched SiGe regions surrounding CoSi and CoSi2 grains at the surface of the film. (Abstract shortened by UMI.)

Surface analytical characterization of Streptavidin/poly(3-hexylthiophene) bilayers for bio-electronic applications

NASA Astrophysics Data System (ADS)

Sportelli, M. C.; Picca, R. A.; Manoli, K.; Re, M.; Pesce, E.; Tapfer, L.; Di Franco, C.; Cioffi, N.; Torsi, L.

2017-10-01

The analytical performance of bioelectronic devices is highly influenced by their fabrication methods. In particular, the final architecture of field-effect transistor biosensors combining spin-cast poly(3-hexylthiophene) (P3HT) film and a biomolecule interlayer deposited on a SiO2/Si substrate can lead to the development of highly performing sensing systems, such as for the case of streptavidin (SA) used for biotin sensing. To gain a better understanding of the quality of the interfacial area, critical is the assessment of the morphological features characteristic of the adopted biolayer deposition protocol, namely: the layer-by-layer (LbL) approach and the spin coating technique. The present study relies on a combined surface spectroscopic and morphological characterization. Specifically, X-ray photoelectron spectroscopy operated in the parallel angle-resolved mode allowed the non-destructive investigation of the in-depth chemical composition of the SA film, alone or in the presence of the P3HT overlayer. Spectroscopic data were supported and corroborated by the results obtained with a Scanning Electron and a Helium Ion microscope investigation performed on the SA layer that provided relevant information on the protein structural arrangement or on its surface morphology. Clear differences emerged between the SA layers prepared by the two approaches, with the layer-by-layer deposition resulting in a smoother and better defined bio-electronic interface. Such findings support the superior analytical performance shown by bioelectronic devices based on LbL-deposited protein layers over spin coated ones.

Microscopic Electronic and Mechanical Properties of Ultra-Thin Layered Materials

DTIC Science & Technology

2016-07-25

Graphene single layers grown by chemical vapor deposition on single crystal Cu substrates are subject to nonuniform physisorption strains that...the observed highly nonuniform strains. 4. Connecting dopant bond type with electronic structure in N-doped graphene (reference [4]) Robust methods

Teflon/SiO₂ Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process.

PubMed

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-04-13

This study proposes a two-photomask process for fabricating amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO₂ combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO₂ deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

High efficiency replicated x-ray optics and fabrication method

DOEpatents

Barbee, Jr., Troy W.; Lane, Stephen M.; Hoffman, Donald E.

2001-01-01

Replicated x-ray optics are fabricated by sputter deposition of reflecting layers on a super-polished reusable mandrel. The reflecting layers are strengthened by a supporting multilayer that results in stronger stress-relieved reflecting surfaces that do not deform during separation from the mandrel. The supporting multilayer enhances the ability to part the replica from the mandrel without degradation in surface roughness. The reflecting surfaces are comparable in smoothness to the mandrel surface. An outer layer is electrodeposited on the supporting multilayer. A parting layer may be deposited directly on the mandrel before the reflecting surface to facilitate removal of the layered, tubular optic device from the mandrel without deformation. The inner reflecting surface of the shell can be a single layer grazing reflection mirror or a resonant multilayer mirror. The resulting optics can be used in a wide variety of applications, including lithography, microscopy, radiography, tomography, and crystallography.

Local epitaxial growth of ZrO2 on Ge (100) substrates by atomic layer epitaxy

NASA Astrophysics Data System (ADS)

Kim, Hyoungsub; Chui, Chi On; Saraswat, Krishna C.; McIntyre, Paul C.

2003-09-01

High-k dielectric deposition processes for gate dielectric preparation on Si surfaces usually result in the unavoidable and uncontrolled formation of a thin interfacial oxide layer. Atomic layer deposition of ˜55-Å ZrO2 film on a Ge (100) substrate using ZrCl4 and H2O at 300 °C was found to produce local epitaxial growth [(001) Ge//(001) ZrO2 and [100] Ge//[100] ZrO2] without a distinct interfacial layer, unlike the situation observed when ZrO2 is deposited using the same method on Si. Relatively large lattice mismatch (˜10%) between ZrO2 and Ge produced a high areal density of interfacial misfit dislocations. Large hysteresis (>200 mV) and high frequency dispersion were observed in capacitance-voltage measurements due to the high density of interface states. However, a low leakage current density, comparable to values obtained on Si substrates, was observed with the same capacitance density regardless of the high defect density.

Dual ion beam assisted deposition of biaxially textured template layers

DOEpatents

Groves, James R.; Arendt, Paul N.; Hammond, Robert H.

2005-05-31

The present invention is directed towards a process and apparatus for epitaxial deposition of a material, e.g., a layer of MgO, onto a substrate such as a flexible metal substrate, using dual ion beams for the ion beam assisted deposition whereby thick layers can be deposited without degradation of the desired properties by the material. The ability to deposit thicker layers without loss of properties provides a significantly broader deposition window for the process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, T.; Hu, M.; Guo, Q.

Here we report a study of printing of electronics using an office use laser printer. The proposed method eliminates those critical disadvantages of solvent-based printing techniques by taking the advantages of electroless deposition and laser printing. The synthesized toner acts as a catalyst for the electroless copper deposition as well as an adhesion-promoting buffer layer between the substrate and deposited copper. The easy metallization of printed patterns and strong metal-substrate adhesion make it an especially effective method for massive production of flexible printed circuits. The proposed process is a high throughput, low cost, efficient, and environmentally benign method for flexiblemore » electronics manufacturing.« less

Atomic layer deposition (ALD): A versatile technique for plasmonics and nanobiotechnology.

PubMed

Im, Hyungsoon; Wittenberg, Nathan J; Lindquist, Nathan C; Oh, Sang-Hyun

2012-02-28

While atomic layer deposition (ALD) has been used for many years as an industrial manufacturing method for microprocessors and displays, this versatile technique is finding increased use in the emerging fields of plasmonics and nanobiotechnology. In particular, ALD coatings can modify metallic surfaces to tune their optical and plasmonic properties, to protect them against unwanted oxidation and contamination, or to create biocompatible surfaces. Furthermore, ALD is unique among thin-film deposition techniques in its ability to meet the processing demands for engineering nanoplasmonic devices, offering conformal deposition of dense and ultra-thin films on high-aspect-ratio nanostructures at temperatures below 100 °C. In this review, we present key features of ALD and describe how it could benefit future applications in plasmonics, nanosciences, and biotechnology.

Pyrolytic Carbon Coatings on Aligned Carbon Nanotube Assemblies and Fabrication of Advanced Carbon Nanotube/Carbon Composites

NASA Astrophysics Data System (ADS)

Faraji, Shaghayegh

Chemical vapor deposition (CVD) is a technique used to create a pyrolytic carbon (PyC) matrix around fibrous preforms in carbon/carbon (C/C) composites. Due to difficulties in producing three-dimensional carbon nanotube (CNT) assemblies, use of nanotubes in CVD fabricated CNT/C composites is limited. This dissertation describes efforts to: 1) Study the microstructure of PyC deposited on CNTs in order to understand the effect of microstructure and morphology of carbon coatings on graphitization behavior of CNT/PyC composites. This understanding helped to suggest a new approach for controlled radial growth of CNTs. 2) Evaluate the properties of CNT/PyC structures as a novel form of CNT assemblies with resilient, anisotropic and tunable properties. PyC was deposited on aligned sheets of nanotubes, drawn from spinnable CNT arras, using CVD of acetylene gas. At longer deposition times, the microstructure of PyC changed from laminar turbostratic carbon to a disordered carbon. For samples with short PyC deposition times (up to 30 minutes), deposited carbon layer rearranged during graphitization treatment and resulted in a crystalline structure where the coating and original tube walls could not be easily differentiated. In contrast, in samples with longer carbon deposition durations, carbon layers close to the surface of the coating remained disordered even after graphitization thermal treatment. Understanding the effect of PyC microstructure transition on graphitization behavior of CNT/PyC composites was used to develop a new method for controlled radial growth of CNTs. Carbon coated aligned CNT sheets were graphitized after each short (20 minutes) carbon deposition cycle. This prevented development of disorder carbon during subsequent PyC deposition cycles. Using cyclic-graphitization method, thick PyC coating layers were successfully graphitized into a crystalline structure that could not be differentiated from the original nanotube walls. This resulted into radial growth of CNTs, from 40 to 100 nm. Infiltration of PyC into stacked layered sheets of aligned CNTs produced resilient foam-like materials that exhibited complete recovery from 90% compressive strain. PyC coated the junctions between nanotubes and also increased their surface roughness. These changes were assumed to be responsible for the resiliency of the, once inelastic, assembly of nanotubes. While nanotubes' alignment resulted in anisotropic properties of the foams, variation in PyC infiltration duration was used to tune the foams' properties. Further investigation into properties of these foams showed promising results for their application as pressure/strain sensor and selective liquid absorbers for oil spill clean ups. Finally, CNT foams were used as novel substrates for growth of secondary nanotube assemblies. In order to achieve that, foams were first coated with alumina buffer layers using atomic layer deposition (ALD) method. New nanotubes were further grown inside the foams by CVD of acetylene over iron nano-particles. Super low density and highly porous structure of the foams allowed for diffusion of catalyst along with growth gasses into their bulk, which resulted in growth of secondary nanotubes throughout the thickness of the foams. The thickness of the alumina buffer layer was shown to influence CNT nucleation density and growth uniformity across the thickness of the foams. Compressive mechanical testing of the foams showed an order of magnitude increase in compression strength after secondary CNT growth.

CuGaS2 and CuGaS2–ZnS Porous Layers from Solution-Processed Nanocrystals

PubMed Central

Guardia, Pablo; Estradé, Sònia; Peiró, Francesca; Cabot, Andreu

2018-01-01

The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS2 (CGS) and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs). We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS–ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs. PMID:29621198

Back contact buffer layer for thin-film solar cells

DOEpatents

Compaan, Alvin D.; Plotnikov, Victor V.

2014-09-09

A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

Mechanical Computing in Microelectromechanical Systems (MEMS)

DTIC Science & Technology

2003-03-01

New York: John Wiley and Sons, Inc., 1968. 25. Helvajian , H . and S. Janson, Microengineering Aerospace Systems, ch. Micro- engineering Space Systems...sacrificial layer. (g)Strip remaining resist. ( h ) Deposit a structural layer(conformal deposition is shown). (i) Deposit resist. (j) Expose resist...layer is then deposited, and assuming a conformal process, the structural layer will follow the topography of the sacrificial layer (Figure 2.9( h

Method for forming metal contacts

DOEpatents

Reddington, Erik; Sutter, Thomas C; Bu, Lujia; Cannon, Alexandra; Habas, Susan E; Curtis, Calvin J; Miedaner, Alexander; Ginley, David S; Van Hest, Marinus Franciscus Antonius Maria

2013-09-17

Methods of forming metal contacts with metal inks in the manufacture of photovoltaic devices are disclosed. The metal inks are selectively deposited on semiconductor coatings by inkjet and aerosol apparatus. The composite is heated to selective temperatures where the metal inks burn through the coating to form an electrical contact with the semiconductor. Metal layers are then deposited on the electrical contacts by light induced or light assisted plating.

Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

DOEpatents

Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

2017-05-09

Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

Method of freeform fabrication by selective gelation of powder suspensions

DOEpatents

Baskaran, S.; Graff, G.L.

1997-12-09

The present invention is a novel method for freeform fabrication. Specifically, the method of solid freeform fabrication has the steps of: (a) preparing a slurry by mixing powder particles with a suspension medium and a gelling polysaccharide; (b) making a layer by depositing an amount of said powder slurry in a confined region; (c) hardening a selected portion of the layer by applying a gelling agent to the selected portion; and (d) repeating steps (b) and (c) to make successive layers and forming a layered object. In many applications, it is desirable to remove unhardened material followed by heating to remove gellable polysaccharide then sintering. 2 figs.

Method of freeform fabrication by selective gelation of powder suspensions

DOEpatents

Baskaran, Suresh; Graff, Gordon L.

1997-01-01

The present invention is a novel method for freeform fabrication. Specifically, the method of solid freeform fabrication has the steps of: (a) preparing a slurry by mixing powder particles with a suspension medium and a gelling polysaccharide; (b) making a layer by depositing an amount of said powder slurry in a confined region; (c) hardening a selected portion of the layer by applying a gelling agent to the selected portion; and (d) repeating steps (b) and (c) to make successive layers and forming a layered object. In many applications, it is desirable to remove unhardened material followed by heating to remove gellable polysaccharide then sintering.

Effect of Pb content and solution concentration of Pb{sub x}TiO{sub 3} seed layer on (100)-texture and ferroelectric/dielectric behavior of PZT (52/48) thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Jian; Batra, Vaishali; Han, Hui

The effect of Pb content and solution concentration of lead titanate (Pb{sub x}TiO{sub 3}) seed layer on the texture and electric properties of Pb{sub 1.1}(Zr{sub 0.52},Ti{sub 0.48})O{sub 3} (PZT) thin films was investigated. A variety of seed layers (y Pb{sub x}TiO{sub 3}) with varying solution concentration (y = 0.02, 0.05, 0.1, and 0.2 M) and Pb content (x = 1.0, 1.05, 1.1, and 1.2) was deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrates using chemical-solution deposition method. PZT films were then deposited on these seed layers using the same process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy investigations of the seed layers confirm change in crystal structuremore » with variation in the solution properties. XRD studies of PZT films deposited on seed layers demonstrate that the seed layer helps in enhancing (100)-texture and suppressing (111)-texture. It was observed that PZT films prepared on seed layers with lower solution concentrations results in highly (100)-textured films, which further helps to improve the electric properties. The polarization and dielectric constant of the PZT films were seen to increase while the coercive field decreased with increase in (100)-texture. Irrespective of the seed layer solution concentration, higher Pb content in the seed layer deteriorates the PZT film properties. Ninety-five percent to ninety-six percent (100)-texture was obtained from thin PZT films deposited on seed layers of 0.02 M solution concentration with 1.05 and 1.10 Pb contents, which is higher than the values reported for thick PZT films. Optimization of both Pb content and solution concentration of the seed layer is a promising route to achieve highly (100)-textured PZT films with improved electric properties.« less

Crystallization of amorphous silicon thin films deposited by PECVD on nickel-metalized porous silicon.

PubMed

Ben Slama, Sonia; Hajji, Messaoud; Ezzaouia, Hatem

2012-08-17

Porous silicon layers were elaborated by electrochemical etching of heavily doped p-type silicon substrates. Metallization of porous silicon was carried out by immersion of substrates in diluted aqueous solution of nickel. Amorphous silicon thin films were deposited by plasma-enhanced chemical vapor deposition on metalized porous layers. Deposited amorphous thin films were crystallized under vacuum at 750°C. Obtained results from structural, optical, and electrical characterizations show that thermal annealing of amorphous silicon deposited on Ni-metalized porous silicon leads to an enhancement in the crystalline quality and physical properties of the silicon thin films. The improvement in the quality of the film is due to the crystallization of the amorphous film during annealing. This simple and easy method can be used to produce silicon thin films with high quality suitable for thin film solar cell applications.

Crystallization of amorphous silicon thin films deposited by PECVD on nickel-metalized porous silicon

PubMed Central

2012-01-01

Porous silicon layers were elaborated by electrochemical etching of heavily doped p-type silicon substrates. Metallization of porous silicon was carried out by immersion of substrates in diluted aqueous solution of nickel. Amorphous silicon thin films were deposited by plasma-enhanced chemical vapor deposition on metalized porous layers. Deposited amorphous thin films were crystallized under vacuum at 750°C. Obtained results from structural, optical, and electrical characterizations show that thermal annealing of amorphous silicon deposited on Ni-metalized porous silicon leads to an enhancement in the crystalline quality and physical properties of the silicon thin films. The improvement in the quality of the film is due to the crystallization of the amorphous film during annealing. This simple and easy method can be used to produce silicon thin films with high quality suitable for thin film solar cell applications. PMID:22901341

Organic thin film transistor with a simplified planar structure

NASA Astrophysics Data System (ADS)

Zhang, Lei; Yu, Jungsheng; Zhong, Jian; Jiang, Yadong

2009-05-01

Organic thin film transistor (OTFT) with a simplified planar structure is described. The gate electrode and the source/drain electrodes of OTFT are processed in one planar structure. And these three electrodes are deposited on the glass substrate by DC sputtering technology using Cr/Ni target. Then the electrode layouts of different width length ratio are made by photolithography technology at the same time. Only one step of deposition and one step of photolithography is needed while conventional process takes at least two steps of deposition and two steps of photolithography. Metal is first prepared on the other side of glass substrate and electrode is formed by photolithography. Then source/drain electrode is prepared by deposition and photolithography on the side with the insulation layer. Compared to conventional process of OTFTs, the process in this work is simplified. After three electrodes prepared, the insulation layer is made by spin coating method. The organic material of polyimide is used as the insulation layer. A small molecular material of pentacene is evaporated on the insulation layer using vacuum deposition as the active layer. The process of OTFTs needs only three steps totally. A semi-auto probe stage is used to connect the three electrodes and the probe of the test instrument. A charge carrier mobility of 0.3 cm2 /V s, is obtained from OTFTs on glass substrates with and on/off current ratio of 105. The OTFTs with the planar structure using simplified process can simplify the device process and reduce the fabrication cost.

Patterned Growth of Carbon Nanotubes or Nanofibers

NASA Technical Reports Server (NTRS)

Delzeit, Lance D.

2004-01-01

A method and apparatus for the growth of carbon nanotubes or nanofibers in a desired pattern has been invented. The essence of the method is to grow the nanotubes or nanofibers by chemical vapor deposition (CVD) onto a patterned catalyst supported by a substrate. The figure schematically depicts salient aspects of the method and apparatus in a typical application. A substrate is placed in a chamber that contains both ion-beam sputtering and CVD equipment. The substrate can be made of any of a variety of materials that include several forms of silicon or carbon, and selected polymers, metals, ceramics, and even some natural minerals and similar materials. Optionally, the substrate is first coated with a noncatalytic metal layer (which could be a single layer or could comprise multiple different sublayers) by ion-beam sputtering. The choice of metal(s) and thickness(es) of the first layer (if any) and its sublayers (if any) depends on the chemical and electrical properties required for subsequent deposition of the catalyst and the subsequent CVD of the carbon nanotubes. A typical first-sublayer metal is Pt, Pd, Cr, Mo, Ti, W, or an alloy of two or more of these elements. A typical metal for the second sublayer or for an undivided first layer is Al at a thickness .1 nm or Ir at a thickness .5 nm. Proper choice of the metal for a second sublayer of a first layer makes it possible to use a catalyst that is chemically incompatible with the substrate. In the next step, a mask having holes in the desired pattern is placed over the coated substrate. The catalyst is then deposited on the coated substrate by ion-beam sputtering through the mask. Optionally, the catalyst could be deposited by a technique other than sputtering and/or patterned by use of photolithography, electron- beam lithography, or another suitable technique. The catalytic metal can be Fe, Co, Ni, or an alloy of two or more of these elements, deposited to a typical thickness in the range from 0.1 to 20 nm.

Process for ion-assisted laser deposition of biaxially textured layer on substrate

DOEpatents

Russo, R.E.; Reade, R.P.; Garrison, S.M.; Berdahl, P.

1995-07-11

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film. 8 figs.

Process for ion-assisted laser deposition of biaxially textured layer on substrate

DOEpatents

Russo, Richard E.; Reade, Ronald P.; Garrison, Stephen M.; Berdahl, Paul

1995-01-01

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film.

Deuterium retention and release behaviours of tungsten and deuterium co-deposited layers

NASA Astrophysics Data System (ADS)

Qiao, L.; Zhang, H. W.; Xu, J.; Chai, L. Q.; Hu, M.; Wang, P.

2018-04-01

Tungsten (W) layer deposited in argon and deuterium atmosphere by magnetron sputtering was used as a model system to study the deuterium (D) retention and release behavior in co-deposited W layer. After deposition several selected samples were exposed in deuterium plasma at 370 K with a flux of 4.0 × 1021 D/(m2 s) up to a fluence of 1.1 × 1025 D/m2. Structures of co-deposited W layers are investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), and the corresponding D retention and release behaviors are studied as functions of deposition and exposure parameters using thermal desorption spectroscopy (TDS). Two main D release peaks were detected from TDS spectra located near 600 and 800 K in these W and D co-deposited layers, and total deuterium retention increased linearly as a function of W layer's thickness. After deuterium plasma exposure, the total D retention amount in W layer increases significantly and D release peak shifts to lower temperature. Clearly, despite the high density of defects expected in co-deposited W layers, the initial deuterium retention before exposure to the deuterium plasma is low even for the samples with a W&D layer. But due to the high densities of defects, during the deuterium plasma exposure the deuterium retention increases faster for co-deposited layer than for the bulk W sample.

Selective layer disordering in III-nitrides with a capping layer

DOEpatents

Wierer, Jr., Jonathan J.; Allerman, Andrew A.

2016-06-14

Selective layer disordering in a doped III-nitride superlattice can be achieved by depositing a dielectric capping layer on a portion of the surface of the superlattice and annealing the superlattice to induce disorder of the layer interfaces under the uncapped portion and suppress disorder of the interfaces under the capped portion. The method can be used to create devices, such as optical waveguides, light-emitting diodes, photodetectors, solar cells, modulators, laser, and amplifiers.

Assessing site formation and assemblage integrity through stone tool refitting at Gruta da Oliveira (Almonda karst system, Torres Novas, Portugal): A Middle Paleolithic case study

PubMed Central

Zilhão, João

2018-01-01

We use stone tool refitting to assess palimpsest formation and stratigraphic integrity in the basal units of the Gruta da Oliveira archeo-stratigraphic sequence, layers 15–27, which TL and U-series dating places in late Marine Isotope Stage (MIS) 5 or early MIS 4. As in most karst contexts, the formation of this succession involved multiple and complex phenomena, including subsidence, bioturbation, carnivore activity and runoff as agents of potential post-depositional disturbance. During phases of stabilization, such as represented by layers 15, 21 and 22, the excavated area was inhabited and refits corroborate that post-depositional displacement is negligible. Layers 23–25 and 16–19 correspond to subdivisions that slice thick geological units primarily formed of material derived from the cave’s entrance via slope dynamics. Refit links are consistent with rapid fill-up of the interstitial spaces found in the Karren-like bedrock (for layers 23–25), or left between large boulders after major roof-collapse events (for layers 16–19). Layers 26 (the “Mousterian Cone”) and 27 are a “bottom-of-hourglass” deposit underlying the main sedimentary body; the refits show that this deposit consists of material derived from layers 15–25 that gravitated through fissures open in the sedimentary column above. Layer 20, at the interface between two major stratigraphic ensembles, requires additional analysis. Throughout, we found significant vertical dispersion along the contact between sedimentary fill and cave wall. Given these findings, a preliminary analysis of technological change across the studied sequence organized the lithic assemblages into five ensembles: layer 15; layers 16–19; layer 20; layers 21–22; layers 23–25. The lower ensembles show higher percentages of flint and of the Levallois method. Uniquely at the site, the two upper ensembles feature bifaces and cleavers. PMID:29451892

Organimetallic Fluorescent Complex Polymers For Light Emitting Applications

DOEpatents

Shi, Song Q.; So, Franky

1997-10-28

A fluorescent complex polymer with fluorescent organometallic complexes connected by organic chain spacers is utilized in the fabrication of light emitting devices on a substantially transparent planar substrate by depositing a first conductive layer having p-type conductivity on the planar surface of the substrate, depositing a layer of a hole transporting and electron blocking material on the first conductive layer, depositing a layer of the fluorescent complex polymer on the layer of hole transporting and electron blocking material as an electron transporting emissive layer and depositing a second conductive layer having n-type conductivity on the layer of fluorescent complex polymer.

Substrate system for spray forming

DOEpatents

Chu, Men G.; Chernicoff, William P.

2000-01-01

A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

Substrate system for spray forming

DOEpatents

Chu, Men G.; Chernicoff, William P.

2002-01-01

A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

Blanch Resistant and Thermal Barrier NiAl Coating Systems for Advanced Copper Alloys

NASA Technical Reports Server (NTRS)

Raj, Sai V. (Inventor)

2005-01-01

A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.

Zr-ZrO2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

NASA Astrophysics Data System (ADS)

Zhang, Qi-Chu; Hadavi, M. S.; Lee, K.-D.; Shen, Y. G.

2003-03-01

High solar performance Zr-ZrO2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO2 or Al2O3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80°C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al2O3/Zr-ZrO2/Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al2O3/Zr-ZrO2/Al solar coating film with two cermet layers has a high solar absorptance value of 0.97 and low hemispherical emittance value of 0.05 at 80°C for a concentration factor of 2. The Al2O3/Zr-ZrO2/Al solar selective coatings with two cermet layers were deposited using dc magnetron sputtering technology. During the deposition of Zr-ZrO2 cermet layer, a Zr metallic target was run in a gas mixture of argon and oxygen. By control of oxygen flow rate the different metal volume fractions in the cermet layers were achieved using dc reactive sputtering. A solar absorptance of 0.96 and normal emittance of 0.05 at 80°C were achieved.

Development of photocatalyst coated fluoropolymer based microreactor using ultrasound for water remediation.

PubMed

Colmenares, Juan Carlos; Nair, Vaishakh; Kuna, Ewelina; Łomot, Dariusz

2018-03-01

Formation of thin layers of photocatalyst in photo-microreactor is a challenging work considering the properties of both catalyst and the microchannel material. The deposition of semiconductor materials on fluoropolymer based microcapillary requires the use of economical methods which are also less energy dependent. The current work introduces a new method for depositing nanoparticles of TiO 2 on the inner walls of a hexafluoropropylene tetrafluoroethylene microtube under mild conditions using ultrasound technique. During the ultrasonication process, changes in the polymer surface were observed and characterized using Attenuated Total Reflectance spectroscopy, Scanning Electron Microscopy and Confocal Microscopy. The rough patches form sites for catalyst deposition resulting in the formation of thin layer of TiO 2 nanoparticles in the inner walls of the microtube. The photocatalytic activity of the TiO 2 coated fluoropolymer based microcapillary was evaluated for removal of phenol present in water. Copyright © 2017 Elsevier B.V. All rights reserved.

Hetero-junction photovoltaic device and method of fabricating the device

DOEpatents

Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

2014-02-10

A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

Formation of Au nano-patterns on various substrates using simplified nano-transfer printing method

NASA Astrophysics Data System (ADS)

Kim, Jong-Woo; Yang, Ki-Yeon; Hong, Sung-Hoon; Lee, Heon

2008-06-01

For future device applications, fabrication of the metal nano-patterns on various substrates, such as Si wafer, non-planar glass lens and flexible plastic films become important. Among various nano-patterning technologies, nano-transfer print method is one of the simplest techniques to fabricate metal nano-patterns. In nano-transfer printing process, thin Au layer is deposited on flexible PDMS mold, containing surface protrusion patterns, and the Au layer is transferred from PDMS mold to various substrates due to the difference of bonding strength of Au layer to PDMS mold and to the substrate. For effective transfer of Au layer, self-assembled monolayer, which has strong bonding to Au, is deposited on the substrate as a glue layer. In this study, complicated SAM layer coating process was replaced to simple UV/ozone treatment, which can activates the surface and form the -OH radicals. Using simple UV/ozone treatments on both Au and substrate, Au nano-pattern can be successfully transferred to as large as 6 in. diameter Si wafer, without SAM coating process. High fidelity transfer of Au nano-patterns to non-planar glass lens and flexible PET film was also demonstrated.

Amorphous transparent conducting oxides in context: Work function survey, trends, and facile modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, T. C.; Zhu, Q.; Buchholz, D. B.

2015-03-01

The work functions of various amorphous and crystalline transparent conducting oxides (TCO5) were measured using Kelvin probe. The films, made by pulsed laser deposition, exhibited varying work functions dependent on the composition and deposition parameters. Tin oxide showed the largest work functions of the oxides measured, while zinc oxide showed the lowest. Binary and ternary combinations of the basis TCOs showed intermediate work functions dependent on the endpoint components. Amorphous TCO5, important in OPV and other technological applications, exhibited similar work functions to their crystalline counterparts. UV/ozone treatment of TCOs temporarily increased the work function, consistent with proposed defect mechanismsmore » associated with near-surface changes in carrier content and Fermi level. Finally, a method for facile adjustment of the work function of commercial TCOs by atomic layer deposition (ALD) capping layers was presented, illustrated by the growth of zinc oxide layers on commercial crystalline ITO films.« less

Comparison of precursor infiltration into polymer thin films via atomic layer deposition and sequential vapor infiltration using in-situ quartz crystal microgravimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padbury, Richard P.; Jur, Jesse S., E-mail: jsjur@ncsu.edu

Previous research exploring inorganic materials nucleation behavior on polymers via atomic layer deposition indicates the formation of hybrid organic–inorganic materials that form within the subsurface of the polymer. This has inspired adaptations to the process, such as sequential vapor infiltration, which enhances the diffusion of organometallic precursors into the subsurface of the polymer to promote the formation of a hybrid organic–inorganic coating. This work highlights the fundamental difference in mass uptake behavior between atomic layer deposition and sequential vapor infiltration using in-situ methods. In particular, in-situ quartz crystal microgravimetry is used to compare the mass uptake behavior of trimethyl aluminummore » in poly(butylene terephthalate) and polyamide-6 polymer thin films. The importance of trimethyl aluminum diffusion into the polymer subsurface and the subsequent chemical reactions with polymer functional groups are discussed.« less

Amorphous transparent conducting oxides in context: Work function survey, trends, and facile modification

NASA Astrophysics Data System (ADS)

Yeh, T. C.; Zhu, Q.; Buchholz, D. B.; Martinson, A. B.; Chang, R. P. H.; Mason, T. O.

2015-03-01

The work functions of various amorphous and crystalline transparent conducting oxides (TCOs) were measured using Kelvin probe. The films, made by pulsed laser deposition, exhibited varying work functions dependent on the composition and deposition parameters. Tin oxide showed the largest work functions of the oxides measured, while zinc oxide showed the lowest. Binary and ternary combinations of the basis TCOs showed intermediate work functions dependent on the endpoint components. Amorphous TCOs, important in OPV and other technological applications, exhibited similar work functions to their crystalline counterparts. UV/ozone treatment of TCOs temporarily increased the work function, consistent with proposed defect mechanisms associated with near-surface changes in carrier content and Fermi level. Finally, a method for facile adjustment of the work function of commercial TCOs by atomic layer deposition (ALD) capping layers was presented, illustrated by the growth of zinc oxide layers on commercial crystalline ITO films.

Magnetic domain observation of FeCo thin films fabricated by alternate monoatomic layer deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohtsuki, T., E-mail: ohtsuki@spring8.or.jp; Kotsugi, M.; Ohkochi, T.

2014-01-28

FeCo thin films are fabricated by alternate monoatomic layer deposition method on a Cu{sub 3}Au buffer layer, which in-plane lattice constant is very close to the predicted value to obtain a large magnetic anisotropy constant. The variation of the in-plane lattice constant during the deposition process is investigated by reflection high-energy electron diffraction. The magnetic domain images are also observed by a photoelectron emission microscope in order to microscopically understand the magnetic structure. As a result, element-specific magnetic domain images show that Fe and Co magnetic moments align parallel. A series of images obtained with various azimuth reveal that themore » FeCo thin films show fourfold in-plane magnetic anisotropy along 〈110〉 direction, and that the magnetic domain structure is composed only of 90∘ wall.« less

Metallated metal-organic frameworks

DOEpatents

Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

2017-02-07

Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

Metallated metal-organic frameworks

DOEpatents

Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

2017-08-22

Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

Paleo-tsunami history along the northern Japan Trench: evidence from Noda Village, northern Sanriku coast, Japan

NASA Astrophysics Data System (ADS)

Inoue, Taiga; Goto, Kazuhisa; Nishimura, Yuichi; Watanabe, Masashi; Iijima, Yasutaka; Sugawara, Daisuke

2017-12-01

Throughout history, large tsunamis have frequently affected the Sanriku area of the Pacific coast of the Tohoku region, Japan, which faces the Japan Trench. Although a few studies have examined paleo-tsunami deposits along the Sanriku coast, additional studies of paleo-earthquakes and tsunamis are needed to improve our knowledge of the timing, recurrence interval, and size of historical and pre-historic tsunamis. At Noda Village, in Iwate Prefecture on the northern Sanriku coast, we found at least four distinct gravelly sand layers based on correlation and chronological data. Sedimentary features such as grain size and thickness suggest that extreme waves from the sea formed these layers. Numerical modeling of storm waves further confirmed that even extremely large storm waves cannot account for the distribution of the gravelly sand layers, suggesting that these deposits are highly likely to have formed by tsunami waves. The numerical method of storm waves can be useful to identify sand layers as tsunami deposits if the deposits are observed far inland or at high elevations. The depositional age of the youngest tsunami deposit is consistent with the AD 869 Jogan earthquake tsunami, a possible predecessor of the AD 2011 Tohoku-oki tsunami. If this is the case, then the study site currently defines the possible northern extent of the AD 869 Jogan tsunami deposit, which is an important step in improving the tsunami source model of the AD 869 Jogan tsunami. Our results suggest that four large tsunamis struck the Noda site between 1100 and 2700 cal BP. The local tsunami sizes are comparable to the AD 2011 and AD 1896 Meiji Sanriku tsunamis, considering the landward extent of each tsunami deposit.

Synthesis, Characterization, and Fabrication of All Inorganic Quantum Dot LEDs

NASA Astrophysics Data System (ADS)

Salman, Haider Baqer

Quantum Dot LEDs with all inorganic materials are investigated in this thesis. The research was motivated by the potential disruptive technology of core shell quantum dots in lighting and display applications. These devices consisted of three main layers: hole transport layer (HTL), electron transport layer (ETL), and emissive layer where the emission of photons occurs. The latter part was formed of CdSe / ZnS core-shell quantum dots, which were synthesized following hot injection method. The ETL and the HTL were formed of zinc oxide nanocrystals and nickel oxide, respectively. Motivated by the low cost synthesis and deposition, NiO and ZnO were synthesized following sol-gel method and deposited using spin coating. The anode of the device was a commercial slide of indium tin oxide deposited on glass substrate while the cathode was a 100 nm aluminum layer that was deposited using an Auto 306T Edwards thermal evaporator. In this research, Raman spectroscopy, micro-photoluminescence spectroscopy, absorbance spectroscopy, X-ray diffraction (XRD) spectroscopy, and atomic force microscopy, were used to characterize the materials. Three sharp peaks were observed in the XRD measurements of the NiO thin film related to three planes and indicated a proper level of crystallinity. The AFM image of the same material indicated a roughness RMS value of 2 nm which was accepted for a device fabrication. The photoluminescence spectrum exhibited a peak at 515 nm for the quantum dots and a peak at 315 nm for the ZnO nanocrystals. The narrow shape of these spectra proved a limited amount of size variation. The transfer characteristics of the fabricated device indicated that the current density ramped up producing green light when the voltage was higher than 5 V to reach 160 mA cm -2 at 9 V.

Development of mirrors for precision laser gyros

NASA Astrophysics Data System (ADS)

Schmitt, Dirk-Roger

1987-11-01

Substrate polishing and interference-layer deposition techniques for the preparation of laser-gyro mirrors to operate at laser wavelength 633 nm and incidence angle 30 deg are investigated experimentally. The importance of high reflectivity and low backscatter for accurate laser-gyro angular-velocity measurement is explained, and the methods used to measure these parameters are outlined. Results for uncoated quartz glass, Zerodur, and Si monocrystal; thin Ag layers; alternate layers of SiO2 and TiO2, and Ag with a thin layer of SiO2 are presented in graphs and micrographs and characterized in detail. It is predicted that further improvements in polishing, the use of ion-beam deposition techniques, and perhaps the replacement of TiO2 with Ta2O5 will give mirrors with lower backscatter values.

Ablation of selected conducting layers by fiber laser

NASA Astrophysics Data System (ADS)

Pawlak, Ryszard; Tomczyk, Mariusz; Walczak, Maria

2014-08-01

Laser Direct Writing (LDW) are used in the manufacture of electronic circuits, pads, and paths in sub millimeter scale. They can also be used in the sensors systems. Ablative laser writing in a thin functional layer of material deposited on the dielectric substrate is one of the LDW methods. Nowadays functional conductive layers are composed from graphene paint or nanosilver paint, indium tin oxide (ITO), AgHTTM and layers containing carbon nanotubes. Creating conducting structures in transparent layers (ITO, AgHT and carbon nanotubes layers) may have special importance e.g. for flexi electronics. The paper presents research on the fabrication of systems of paths and appropriate pattern systems of paths and selected electronic circuits in AgHTTM and ITO layers deposited on glass and polymer substrates. An influence of parameters of ablative fiber laser treatment in nanosecond regime as well as an influence of scanning mode of laser beam on the pattern fidelity and on electrical parameters of a generated circuit was investigated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xing, Yingjie, E-mail: xingyj@pku.edu.cn; Li, Shuai; Wang, Guiwei

The donor/acceptor heterojunction plays an important role in organic solar cells. An investigation of band bending in the donor/acceptor heterojunction is helpful in analysis of the charge transport behavior and for the improvement of the device performance. In this work, we report an approach for detection of band bending in a donor/acceptor heterojunction that has been prepared on a small and sharp tungsten tip. In situ field emission measurements are performed after the deposition process, and a linear Fowler-Nordheim plot is obtained from the fresh organic film surface. The thickness-dependent work function is then measured in the layer-by-layer deposited heterojunction.more » Several different types of heterojunction (zinc phthalocyanine (ZnPc)/C60, copper phthalocyanine (CuPc)/3,4,9,10-perylenetetracarboxylic bisbenzimidazole, and CuPc/C60) are fabricated and analyzed. The different charge transfer directions in the heterojunctions are distinguished by field emission measurements. The calculation method used to determine the band bending is then discussed in detail. A triple layer heterojunction (C60/ZnPc/CuPc) is also analyzed using this method. A small amount of band bending is measured in the outer CuPc layer. This method provides an independent reference method for determination of the band bending in an organic heterojunction that will complement photoemission spectroscopy and current-voltage measurement methods.« less

Design and fabrication of a reflection far ultraviolet polarizer and retarder

NASA Technical Reports Server (NTRS)

Kim, Jongmin; Zukic, Muamer; Wilson, Michele M.; Torr, Douglas G.

1993-01-01

New methods have been developed for the design of a far ultraviolet multilayer reflection polarizer and retarder. A MgF2/Al/MgF2 three-layer structure deposited on a thick opaque Al film (substrate) is used for the design of polarizers and retarders. The induced transmission and absorption method is used for the design of a polarizer and layer-by-layer electric field calculation method is used for the design of a quarterwave retarder. In order to fabricate these designs in a conventional high vacuum chamber, we have to minimize the oxidation of the Al layers and somehow characterize the oxidized layer. X-ray photoelectron spectroscopy is used to investigate the amount and profile of oxidation. Depth profiling results and a seven layer oxidation model are presented.

Use of double-layer ITO films in reflective contacts for blue and near-UV LEDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markov, L. K., E-mail: l.markov@mail.ioffe.ru; Smirnova, I. P.; Pavluchenko, A. S.

2014-12-15

The structural and optical properties of multilayer ITO/SiO{sub 2}/Ag composites are studied. In these composites, the ITO (indium-tin oxide) layer is produced by two different methods: electron-beam evaporation and a combined method including electron-beam evaporation and subsequent magnetron sputtering. It is shown that the reflectance of the composite based on the ITO film produced by electron-beam evaporation is substantially lower. This can be attributed to the strong absorption of light at both boundaries of the SiO{sub 2} layer, which results from the complex surface profile of ITO films deposited by electron-beam evaporation. Samples with a film deposited by the combinedmore » method have a reflectance of about 90% at normal light incidence, which, combined with their higher electrical conductivity, makes these samples advantageous for use as reflective contacts to the p-type region of AlInGaN light-emitting diodes of the flip-chip design.« less

Thermal conductivity of ZrO2-4mol%Y2O3 thin coatings by pulsed thermal imaging method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Byung-Koog; Sun, Jiangang; Kim, Seongwon

Thin ZrO2-4mol% Y2O3 coatings were deposited onto ZrO2 substrates by electron beam-physical vapor deposition. The coated samples revealed a feather-like columnar microstructure. The main phase of the ZrO2-4mol% Y2O3 coatings was the tetragonal phase. To evaluate the influence of the coating’s thickness on the thermal conductivity of thin ZrO2-4mol% Y2O3 coatings, the pulsed thermal imaging method was employed to obtain the thermal conductivity of the coating layer in the two-layer (coating and substrate) samples with thickness between 56 and 337 micrometers. The thermal conductivity of the coating layer was successfully evaluated and compared well with those obtained by the lasermore » flash method for similar coatings. The thermal conductivity of coatings shows an increasing tendency with an increase in the coating’s thickness.« less

Ceramic honeycomb structures and the method thereof

NASA Technical Reports Server (NTRS)

Riccitiello, Salvatore R. (Inventor); Cagliostro, Domenick E. (Inventor)

1987-01-01

The subject invention pertains to a method of producing an improved composite-composite honeycomb structure for aircraft or aerospace use. Specifically, the subject invention relates to a method for the production of a lightweight ceramic-ceramic composite honeycomb structure, which method comprises: (1) pyrolyzing a loosely woven fabric/binder having a honeycomb shape and having a high char yield and geometric integrity after pyrolysis at between about 700 and 1,100 C; (2) substantially evenly depositing at least one layer of ceramic material on the pyrolyzed fabric/binder of step (1); (3) recovering the coated ceramic honeycomb structure; (4) removing the pyrolyzed fabric/binder of the structure of step (3) by slow pyrolysis at between 700 and 1000 C in between about a 2 to 5% by volume oxygen atmosphere for between about 0.5 and 5 hr.; and (5) substantially evenly depositing on and within the rigid hollow honeycomb structure at least one additional layer of the same or a different ceramic material by chemical vapor deposition and chemical vapor infiltration. The honeycomb shaped ceramic articles have enhanced physical properties and are useful in aircraft and aerospace uses.

Thermal release of D2 from new Be-D co-deposits on previously baked co-deposits

NASA Astrophysics Data System (ADS)

Baldwin, M. J.; Doerner, R. P.

2015-12-01

Past experiments and modeling with the TMAP code in [1, 2] indicated that Be-D co-deposited layers are less (time-wise) efficiently desorbed of retained D in a fixed low-temperature bake, as the layer grows in thickness. In ITER, beryllium rich co-deposited layers will grow in thickness over the life of the machine. Although, compared with the analyses in [1, 2], ITER presents a slightly different bake efficiency problem because of instances of prior tritium recover/control baking. More relevant to ITER, is the thermal release from a new and saturated co-deposit layer in contact with a thickness of previously-baked, less-saturated, co-deposit. Experiments that examine the desorption of saturated co-deposited over-layers in contact with previously baked under-layers are reported and comparison is made to layers of the same combined thickness. Deposition temperatures of ∼323 K and ∼373 K are explored. It is found that an instance of prior bake leads to a subtle effect on the under-layer. The effect causes the thermal desorption of the new saturated over-layer to deviate from the prediction of the validated TMAP model in [2]. Instead of the D thermal release reflecting the combined thickness and levels of D saturation in the over and under layer, experiment differs in that, i) the desorption is a fractional superposition of desorption from the saturated over-layer, with ii) that of the combined over and under -layer thickness. The result is not easily modeled by TMAP without the incorporation of a thin BeO inter-layer which is confirmed experimentally on baked Be-D co-deposits using X-ray micro-analysis.

Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells.

PubMed

Jung, Yen-Sook; Hwang, Kyeongil; Scholes, Fiona H; Watkins, Scott E; Kim, Dong-Yu; Vak, Doojin

2016-02-08

We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%.

Chemical precursor impact on the properties of Cu{sub 2}ZnSnS{sub 4} absorber layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vashistha, Indu B., E-mail: indu-139@yahoo.com; Sharma, S. K.; Sharma, Mahesh C.

2016-04-13

In present work impact of different chemical precursor on the deposition of solar absorber layer Cu{sub 2}ZnSnS{sub 4} (CZTS) were studied by Chemical Bath Deposition (CBD) method without using expensive vacuum facilities and followed by annealing. As compared to the other deposition methods, CBD method is interesting one because it is simple, reproducible, non-hazardous, cost effective and well suited for producing large-area thin films at low temperatures, although effect of precursors and concentration plays a vital role in the deposition. So, the central theme of this work is optimizing and controlling of chemical reactions for different chemical precursors. Further Effectmore » of different chemical precursors i.e. sulphate and chloride is analyzed by structural, morphological, optical and electrical properties. The X-ray diffraction (XRD) of annealed CZTS thin film revealed that films were polycrystalline in nature with kestarite tetragonal crystal structure. The Atomic Force micrographs (AFM) images indicated total coverage compact film and as well as growth of crystals. The band gap of annealed CZTS films was found in the range of optimal band gap by absorption spectroscopy.« less

Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells

PubMed Central

Jung, Yen-Sook; Hwang, Kyeongil; Scholes, Fiona H.; Watkins, Scott E.; Kim, Dong-Yu; Vak, Doojin

2016-01-01

We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%. PMID:26853266

Method for materials deposition by ablation transfer processing

DOEpatents

Weiner, K.H.

1996-04-16

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs. 1 fig.

PROMETHEE II: A knowledge-driven method for copper exploration

NASA Astrophysics Data System (ADS)

Abedi, Maysam; Ali Torabi, S.; Norouzi, Gholam-Hossain; Hamzeh, Mohammad; Elyasi, Gholam-Reza

2012-09-01

This paper describes the application of a well-known Multi Criteria Decision Making (MCDM) technique called Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE II) to explore porphyry copper deposits. Various raster-based evidential layers involving geological, geophysical, and geochemical geo-datasets are integrated to prepare a mineral prospectivity mapping (MPM). In a case study, thirteen layers of the Now Chun copper deposit located in the Kerman province of Iran are used to explore the region of interest. The PROMETHEE II technique is applied to produce the desired MPM, and the outputs are validated using twenty-one boreholes that have been classified into five classes. This proposed method shows a high performance when providing the MPM while reducing the cost of exploratory drilling in the study area.

Method for thermally spraying crack-free mullite coatings on ceramic-based substrates

NASA Technical Reports Server (NTRS)

Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor); Heidorn, Raymond W. (Inventor)

2001-01-01

A process for depositing a mullite coating on a silicon-based material, such as those used to form articles exposed to high temperatures and including the hostile thermal environment of a gas turbine engine. The process is generally to thermally spray a mullite powder to form a mullite layer on a substrate, in which the thermal spraying process is performed so that the mullite powder absorbs a sufficient low level of energy from the thermal source to prevent evaporation of silica from the mullite powder. Processing includes deposition parameter adjustments or annealing to maintain or reestablish phase equilibrium in the mullite layer, so that through-thickness cracks in the mullite layer are avoided.

Method for thermally spraying crack-free mullite coatings on ceramic-based substrates

NASA Technical Reports Server (NTRS)

Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor); Heidorn, Raymond W. (Inventor)

2000-01-01

A process for depositing a mullite coating on a silicon-based material, such as those used to form articles exposed to high temperatures and including the hostile thermal environment of a gas turbine engine. The process is generally to thermally spray a mullite powder to form a mullite layer on a substrate, in which the thermal spraying process is performed so that the mullite powder absorbs a sufficient low level of energy from the thermal source to prevent evaporation of silica from the mullite powder. Processing includes deposition parameter adjustments or annealing to maintain or reestablish phase equilibrium in the mullite layer, so that through-thickness cracks in the mullite layer are avoided.

Graphene decorated microelectrodes for simultaneous detection of ascorbic, dopamine, and folic acids by means of chemical vapor deposition

NASA Astrophysics Data System (ADS)

Namdar, N.; Hassanpour Amiri, M.; Dehghan Nayeri, F.; Gholizadeh, A.; Mohajerzadeh, S.

2015-09-01

In this paper, high quality and large area graphene layers were synthesized using thermal chemical vapour deposition on copper foil substrates. We use graphene incorporated electrodes to measure simultaneously ascorbic acid, dopamine and folic acid. Cyclic voltammetry and differential pulse voltammetry methods were used to evaluate electrochemical behaviour of the grown graphene layers. The graphene-modified electrode shows large electrochemical potential difference compared to bare gold electrodes with higher current responses. Also our fabricated electrodes configuration can be used easily for microfluidic analysis.

Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

NASA Astrophysics Data System (ADS)

Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

2016-04-01

Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

Stable, Microfabricated Thin Layer Chromatography Plates without Volume Distortion on Patterned, Carbon and Al2O3-Primed Carbon Nanotube Forests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, David S.; Kanyal, Supriya S.; Gupta, Vipul

2012-09-28

In a recent report (Song, J.; et al., Advanced Functional Materials 2011, 21, 1132-1139) some of us described the fabrication of thin layer chromatography (TLC) plates from patterned carbon nanotube (CNT) forests, which were directly infiltrated/coated with silicon by low pressure chemical vapor deposition (LPCVD) of silicon using SiH4. Following infiltration, the nanotubes were removed from the assemblies and the silicon simultaneously converted to SiO2 in a high temperature oxidation step. However, while straightforward, this process had some shortcomings, not the least of which was some distortion of the lithographically patterned features during the volume expansion that accompanied oxidation. Hereinmore » we overcome theis issue and also take substantial steps forward in the microfabrication of TLC plates by showing: (i) A new method for creating an adhesion promotion layer on CNT forests by depositing a few nanometers of carbon followed by atomic layer deposition (ALD) of Al2O3. This method for appears to be new, and X-ray photoelectron spectroscopy confirms the expected presence of oxygen after carbon deposition. ALD of Al2O3 alone and in combination with the carbon on patterned CNT forests was also explored as an adhesion promotion layer for CNT forest infiltration. (ii) Rapid, conformal deposition of an inorganic material that does not require subsequent oxidation: fast pseudo-ALD growth of SiO2 via alumina catalyzed deposition of tris(tert-butoxy)silanol onto the carbon/Al2O3-primed CNT forests. (iii) Faithful reproduction of the features in the masks used to microfabricate the TLC plates (M-TLC) this advance springs from the previous two points. (iv) A bonded (amino) phase on a CNT-templated microfabricated TLC plate. (v) Fast, highly efficient (125,000 - 225,000 N/m) separations of fluorescent dyes on M-TLC plates. (vi) Extensive characterization of our new materials by TEM, SEM, EDAX, DRIFT, and XPS. (vii) A substantially lower process temperature for the removal of the CNT scaffold as a result of the (already oxidized) materials used in this study.« less

BEOL compatible high tunnel magneto resistance perpendicular magnetic tunnel junctions using a sacrificial Mg layer as CoFeB free layer cap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swerts, J., E-mail: Johan.Swerts@imec.be; Mertens, S.; Lin, T.

Perpendicularly magnetized MgO-based tunnel junctions are envisaged for future generation spin-torque transfer magnetoresistive random access memory devices. Achieving a high tunnel magneto resistance and preserving it together with the perpendicular magnetic anisotropy during BEOL CMOS processing are key challenges to overcome. The industry standard technique to deposit the CoFeB/MgO/CoFeB tunnel junctions is physical vapor deposition. In this letter, we report on the use of an ultrathin Mg layer as free layer cap to protect the CoFeB free layer from sputtering induced damage during the Ta electrode deposition. When Ta is deposited directly on CoFeB, a fraction of the surface ofmore » the CoFeB is sputtered even when Ta is deposited with very low deposition rates. When depositing a thin Mg layer prior to Ta deposition, the sputtering of CoFeB is prevented. The ultra-thin Mg layer is sputtered completely after Ta deposition. Therefore, the Mg acts as a sacrificial layer that protects the CoFeB from sputter-induced damage during the Ta deposition. The Ta-capped CoFeB free layer using the sacrificial Mg interlayer has significantly better electrical and magnetic properties than the equivalent stack without protective layer. We demonstrate a tunnel magneto resistance increase up to 30% in bottom pinned magnetic tunnel junctions and tunnel magneto resistance values of 160% at resistance area product of 5 Ω.μm{sup 2}. Moreover, the free layer maintains perpendicular magnetic anisotropy after 400 °C annealing.« less

The Grain-size Patchiness of Braided Gravel-Bed Streams: Example of the Urumqi River (northeast Tian Shan, China)

NASA Astrophysics Data System (ADS)

Guerit, L.; Barrier, L.; Narteau, C.; Métivier, F.; Liu, Y.; Lajeunesse, E.; Gayer, E.; Malverti, L.; Meunier, P.; Ye, B.

2012-04-01

In gravel-beds rivers, sediments are sorted into patches of different grain-sizes. For single-thread streams, it has long been shown that this local granulometric sorting is closely linked to the channel morpho-sedimentary elements. For braided streams, this relation is still unclear. In such rivers, many observations of vertical sediment sorting has led to the definition of a surface and a subsurface layers. Because of this common stratification, methods for sampling gravel-bed rivers have been divided in two families. The surface layer is generally sampled by surface methods and the subsurface layer by volumetric methods. Yet, the equivalency between the two kind of techniques is still a key question. In this study, we characterized the grain-size distribution of the surface layer of the Urumqi River, a shallow braided gravel-bed river in China, by surface-count (Wolman grid-by-number) and volumetric (sieve-by-weight) sampling methods. An analysis of two large samples (212 grains and 3226 kg) show that these two methods are equivalent to characterize the river-bed surface layer. Then, we looked at the grain-size distributions of the river-bed morpho-sedimentary elements: (1) chutes at flow constrictions, which pass downstream to (2) anabranches and (3) bars at flow expansions. Using both sampling methods, we measured the diameter of more than 2300 grains and weight more than 6000 kg of grains larger than 4 mm. Our results show that the three morpho-sedimentary elements correspond only to two kinds of grain-size patches: (1) chutes composed of one coarse-grained top layer lying on finer deposits, and (2) anabranches and bars made up of finer-grained deposits more homogeneous in depth. On the basis of these quantitative observations, together with the concave or convex morphology of the different elements, we propose that chute patches form by erosion and transit with size-selective entrainment, whereas anabranch and bar patches rather develop and migrate by transit and deposition. These patch features may be typical of shallow braided gravel-bed rivers and should be considered in future works about on bedload transport processes and their geomorphologic and stratigraphic results.

Buffer layers on metal surfaces having biaxial texture as superconductor substrates

DOEpatents

Paranthaman, Mariappan; Lee, Dominic F.; Kroeger, Donald M.; Goyal, Amit

2000-01-01

Buffer layer architectures are epitaxially deposited on biaxially-textured rolled substrates of nickel and/or copper and their alloys for high current conductors, and more particularly buffer layer architectures such as Y.sub.2 O.sub.3 /Ni, YSZ/Y.sub.2 O.sub.3 /Ni, RE.sub.2 O.sub.3 /Ni, (RE=Rare Earth), RE.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Ni, RE.sub.2 O.sub.3 /CeO.sub.2 /Ni, and RE.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Ni, Y.sub.2 O.sub.3 /Cu, YSZ/Y.sub.2 O.sub.3 /Cu, RE.sub.2 O.sub.3 /Cu, RE.sub.2 O.sub.3 /Y.sub.2 O.sub.3 /Cu, RE.sub.2 O.sub.3 /CeO.sub.2 /Cu, and RE.sub.2 O.sub.3 /YSZ/CeO.sub.2 /Cu. Deposition methods include physical vapor deposition techniques which include electron-beam evaporation, rf magnetron sputtering, pulsed laser deposition, thermal evaporation, and solution precursor approaches, which include chemical vapor deposition, combustion CVD, metal-organic decomposition, sol-gel processing, and plasma spray.

Interface and permittivity simultaneous reconstruction in electrical capacitance tomography based on boundary and finite-elements coupling method

PubMed Central

Ren, Shangjie; Dong, Feng

2016-01-01

Electrical capacitance tomography (ECT) is a non-destructive detection technique for imaging the permittivity distributions inside an observed domain from the capacitances measurements on its boundary. Owing to its advantages of non-contact, non-radiation, high speed and low cost, ECT is promising in the measurements of many industrial or biological processes. However, in the practical industrial or biological systems, a deposit is normally seen in the inner wall of its pipe or vessel. As the actual region of interest (ROI) of ECT is surrounded by the deposit layer, the capacitance measurements become weakly sensitive to the permittivity perturbation occurring at the ROI. When there is a major permittivity difference between the deposit and the ROI, this kind of shielding effect is significant, and the permittivity reconstruction becomes challenging. To deal with the issue, an interface and permittivity simultaneous reconstruction approach is proposed. Both the permittivity at the ROI and the geometry of the deposit layer are recovered using the block coordinate descent method. The boundary and finite-elements coupling method is employed to improve the computational efficiency. The performance of the proposed method is evaluated with the simulation tests. This article is part of the themed issue ‘Supersensing through industrial process tomography’. PMID:27185960

Adhesion layer for etching of tracks in nuclear trackable materials

DOEpatents

Morse, Jeffrey D.; Contolini, Robert J.

2001-01-01

A method for forming nuclear tracks having a width on the order of 100-200 nm in nuclear trackable materials, such as polycarbonate (LEXAN) without causing delamination of the LEXAN. The method utilizes an adhesion film having a inert oxide which allows the track to be sufficiently widened to >200 nm without delamination of the nuclear trackable materials. The adhesion film may be composed of a metal such as Cr, Ni, Au, Pt, or Ti, or composed of a dielectric having a stable surface, such as silicon dioxide (SiO.sub.2), silicon nitride (SiN.sub.x), and aluminum oxide (AlO). The adhesion film can either be deposited on top of the gate metal layer, or if the properties of the adhesion film are adequate, it can be used as the gate layer. Deposition of the adhesion film is achieved by standard techniques, such as sputtering or evaporation.

Pulsed-Plasma Physical Vapor Deposition Approach Toward the Facile Synthesis of Multilayer and Monolayer Graphene for Anticoagulation Applications.

PubMed

Vijayaraghavan, Rajani K; Gaman, Cezar; Jose, Bincy; McCoy, Anthony P; Cafolla, Tony; McNally, Patrick J; Daniels, Stephen

2016-02-01

We demonstrate the growth of multilayer and single-layer graphene on copper foil using bipolar pulsed direct current (DC) magnetron sputtering of a graphite target in pure argon atmosphere. Single-layer graphene (SG) and few-layer graphene (FLG) films are deposited at temperatures ranging from 700 °C to 920 °C within <30 min. We find that the deposition and post-deposition annealing temperatures influence the layer thickness and quality of the graphene films formed. The films were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and optical transmission spectroscopy techniques. Based on the above studies, a diffusion-controlled mechanism was proposed for the graphene growth. A single-step whole blood assay was used to investigate the anticoagulant activity of graphene surfaces. Platelet adhesion, activation, and morphological changes on the graphene/glass surfaces, compared to bare glass, were analyzed using fluorescence microscopy and SEM techniques. We have found significant suppression of the platelet adhesion, activation, and aggregation on the graphene-covered surfaces, compared to the bare glass, indicating the anticoagulant activity of the deposited graphene films. Our production technique represents an industrially relevant method for the growth of SG and FLG for various applications including the biomedical field.

Development of the α-IGZO/Ag/α-IGZO Triple-Layer Structure Films for the Application of Transparent Electrode.

PubMed

Chen, Kun-Neng; Yang, Cheng-Fu; Wu, Chia-Ching; Chen, Yu-Hsin

2017-02-24

We investigated the structural, optical, and electrical properties of amorphous IGZO/silver/amorphous IGZO (α-IGZO/Ag/α-IGZO) triple-layer structures that were deposited at room temperature on Eagle XG glass and flexible polyethylene terephthalate substrates through the sputtering method. Thin Ag layers with different thicknesses were inserted between two IGZO layers to form a triple-layer structure. Ag was used because of its lower absorption and resistivity. Field emission scanning electron microscopy measurements of the triple-layer structures revealed that the thicknesses of the Ag layers ranged from 13 to 41 nm. The thickness of the Ag layer had a large effect on the electrical and optical properties of the electrodes. The optimum thickness of the Ag metal thin film could be evaluated according to the optical transmittance, electrical conductivity, and figure of merit of the electrode. This study demonstrates that the α-IGZO/Ag/α-IGZO triple-layer transparent electrode can be fabricated with low sheet resistance (4.2 Ω/□) and high optical transmittance (88.1%) at room temperature without postannealing processing on the deposited thin films.

Metal Organic Chemical Vapor Deposition of Oxide Films for Advanced Applications

DTIC Science & Technology

2000-06-01

coatings , photovoltaics, touch sensitive controls, electromagnetic shielding (as found on microwave ovens and stealth fighters), static dissipaters, and so...depositing high quality films. The methods are physical vapor deposition ( PVD ), spin/mist deposition, (CVD), and alternating layer (AL) CVD. PVD ...PZT & SBT, YBa2Cu3O, CeO, InO, TCOs, Varistors Ta2O5 , ZrO, MnO, HfO, CeO, MnO, MgO SAW/microwave Silicon/: Si, SiGe, SiGeC, �. Opto-electronics

Thickness scaling of atomic-layer-deposited HfO2 films and their application to wafer-scale graphene tunnelling transistors

PubMed Central

Jeong, Seong-Jun; Gu, Yeahyun; Heo, Jinseong; Yang, Jaehyun; Lee, Chang-Seok; Lee, Min-Hyun; Lee, Yunseong; Kim, Hyoungsub; Park, Seongjun; Hwang, Sungwoo

2016-01-01

The downscaling of the capacitance equivalent oxide thickness (CET) of a gate dielectric film with a high dielectric constant, such as atomic layer deposited (ALD) HfO2, is a fundamental challenge in achieving high-performance graphene-based transistors with a low gate leakage current. Here, we assess the application of various surface modification methods on monolayer graphene sheets grown by chemical vapour deposition to obtain a uniform and pinhole-free ALD HfO2 film with a substantially small CET at a wafer scale. The effects of various surface modifications, such as N-methyl-2-pyrrolidone treatment and introduction of sputtered ZnO and e-beam-evaporated Hf seed layers on monolayer graphene, and the subsequent HfO2 film formation under identical ALD process parameters were systematically evaluated. The nucleation layer provided by the Hf seed layer (which transforms to the HfO2 layer during ALD) resulted in the uniform and conformal deposition of the HfO2 film without damaging the graphene, which is suitable for downscaling the CET. After verifying the feasibility of scaling down the HfO2 thickness to achieve a CET of ~1.5 nm from an array of top-gated metal-oxide-graphene field-effect transistors, we fabricated graphene heterojunction tunnelling transistors with a record-low subthreshold swing value of <60 mV/dec on an 8″ glass wafer. PMID:26861833

Stratigraphy of the layered terrain in Valles Marineris, Mars

NASA Technical Reports Server (NTRS)

Komatsu, G.; Strom, Roger G.

1991-01-01

The layered terrain in Valles Marineris provides information about its origin and the geologic history of this canyon system. Whether the terrain is sedimentary material deposited in a dry or lacustrine environment, or volcanic material related to the tectonics of the canyon is still controversial. However, recent studies of Gangis Layered Terrain suggests a cyclic sequence of deposition and erosion under episodic lacustrine conditions. The stratigraphic studies are extended to four other occurrences of layered terrains in Valles Marineris in an attempt to correlate and distinguish between depositional environments. The Juvantae Chasma, Hebes Chasma, Ophir and Candor Chasmata, Melas Chasma, and Gangis Layered Terrain were examined. Although there are broad similarities among the layered terrains, no two deposits are exactly alike. This suggests that there was no synchronized regional depositional processes to form all the layered deposits. However, the similar erosional style of the lower massive weakly bedded unit in Hebes, Gangis, and Ophir-Candor suggests it may have been deposited under similar circumstances.

Low temperature production of large-grain polycrystalline semiconductors

DOEpatents

Naseem, Hameed A [Fayetteville, AR; Albarghouti, Marwan [Loudonville, NY

2007-04-10

An oxide or nitride layer is provided on an amorphous semiconductor layer prior to performing metal-induced crystallization of the semiconductor layer. The oxide or nitride layer facilitates conversion of the amorphous material into large grain polycrystalline material. Hence, a native silicon dioxide layer provided on hydrogenated amorphous silicon (a-Si:H), followed by deposited Al permits induced crystallization at temperatures far below the solid phase crystallization temperature of a-Si. Solar cells and thin film transistors can be prepared using this method.

Full coverage of perovskite layer onto ZnO nanorods via a modified sequential two-step deposition method for efficiency enhancement in perovskite solar cells

NASA Astrophysics Data System (ADS)

Ruankham, Pipat; Wongratanaphisan, Duangmanee; Gardchareon, Atcharawon; Phadungdhitidhada, Surachet; Choopun, Supab; Sagawa, Takashi

2017-07-01

Full coverage of perovskite layer onto ZnO nanorod substrates with less pinholes is crucial for achieving high-efficiency perovskite solar cells. In this work, a two-step sequential deposition method is modified to achieve an appropriate property of perovskite (MAPbI3) film. Surface treatment of perovskite layer and its precursor have been systematically performed and their morphologies have been investigated. By pre-wetting of lead iodide (PbI2) and letting it dry before reacting with methylammonium iodide (MAI) provide better coverage of perovskite film onto ZnO nanorod substrate than one without any treatment. An additional MAI deposition followed with toluene drop-casting technique on the perovskite film is also found to increase the coverage and enhance the transformation of PbI2 to MAPbI3. These lead to longer charge carrier lifetime, resulting in an enhanced power conversion efficiency (PCE) from 1.21% to 3.05%. The modified method could been applied to a complex ZnO nanorods/TiO2 nanoparticles substrate. The enhancement in PCE to 3.41% is observed. These imply that our introduced method provides a simple way to obtain the full coverage and better transformation to MAPbI3 phase for enhancement in performances of perovskite solar cells.

Structure and properties of polyaniline nanocomposite coatings containing gold nanoparticles formed by low-energy electron beam deposition

NASA Astrophysics Data System (ADS)

Wang, Surui; Rogachev, A. A.; Yarmolenko, M. A.; Rogachev, A. V.; Xiaohong, Jiang; Gaur, M. S.; Luchnikov, P. A.; Galtseva, O. V.; Chizhik, S. A.

2018-01-01

Highly ordered conductive polyaniline (PANI) coatings containing gold nanoparticles were prepared by low-energy electron beam deposition method, with emeraldine base and chloroauric acid used as target materials. The molecular and chemical structure of the layers was studied by Fourier transform infrared, Raman, UV-vis and X-ray photoelectron spectroscopy. The morphology of the coatings was investigated by atomic force and transmission electron microscopy. Conductive properties were obtained by impedance spectroscopy method and scanning spreading resistance microscopy mode at the micro- and nanoscale. It was found that the emeraldine base layers formed from the products of electron-beam dispersion have extended, non-conductive polymer chains with partially reduced structure, with the ratio of imine and amine groups equal to 0.54. In case of electron-beam dispersion of the emeraldine base and chloroauric acid, a protoemeraldine structure is formed with conductivity 0.1 S/cm. The doping of this structure was carried out due to hydrochloric acid vapor and gold nanoparticles formed by decomposition of chloroauric acid, which have a narrow size distribution, with the most probable diameter about 40 nm. These gold nanoparticles improve the conductivity of the thin layers of PANI + Au composite, promoting intra- and intermolecular charge transfer of the PANI macromolecules aligned along the coating surface both at direct and alternating voltage. The proposed deposition method of highly oriented, conductive nanocomposite PANI-based coatings may be used in the direct formation of functional layers on conductive and non-conductive substrates.

Investigation of different C-backings for targets

NASA Astrophysics Data System (ADS)

Hübner, Annett; Kindler, Birgit; Lommel, Bettina; Steiner, Jutta; Yakusheva, Vera; Khuyagbaatar, J.; Hinde, David J.; Dasgupta, Mahananda

2018-05-01

For a special application, carbon-backings with a very flat surface, microscopically as well as macroscopically, were needed as backings for targets of enriched isotopes. However, betaine-sucrose routinely applied at GSI as parting agent for carbon deposition results in a microscopically rough surface which was not perfectly satisfying the experimental requirements. For these targets we investigated the carbon-backing quality in relation to the applied different parting agents and different deposition processes. In this paper we report on the yield, on the structure of the carbon layers and the deposited target layer of 208PbS, 206PbS, and 142NdF3 depending on the parting agent, the thickness and the deposition methods. We report on elastic scattering experiments with a 48Ti-beam demonstrating the influence of the structure of the carbon backing on the experimental results.

Photovoltaic healing of non-uniformities in semiconductor devices

DOEpatents

Karpov, Victor G.; Roussillon, Yann; Shvydka, Diana; Compaan, Alvin D.; Giolando, Dean M.

2006-08-29

A method of making a photovoltaic device using light energy and a solution to normalize electric potential variations in the device. A semiconductor layer having nonuniformities comprising areas of aberrant electric potential deviating from the electric potential of the top surface of the semiconductor is deposited onto a substrate layer. A solution containing an electrolyte, at least one bonding material, and positive and negative ions is applied over the top surface of the semiconductor. Light energy is applied to generate photovoltage in the semiconductor, causing a redistribution of the ions and the bonding material to the areas of aberrant electric potential. The bonding material selectively bonds to the nonuniformities in a manner such that the electric potential of the nonuniformities is normalized relative to the electric potential of the top surface of the semiconductor layer. A conductive electrode layer is then deposited over the top surface of the semiconductor layer.

Fabrication of CIS Absorber Layers with Different Thicknesses Using A Non-Vacuum Spray Coating Method

PubMed Central

Diao, Chien-Chen; Kuo, Hsin-Hui; Tzou, Wen-Cheng; Chen, Yen-Lin; Yang, Cheng-Fu

2014-01-01

In this study, a new thin-film deposition process, spray coating method (SPM), was investigated to deposit the high-densified CuInSe2 absorber layers. The spray coating method developed in this study was a non-vacuum process, based on dispersed nano-scale CuInSe2 precursor and could offer a simple, inexpensive, and alternative formation technology for CuInSe2 absorber layers. After spraying on Mo/glass substrates, the CuInSe2 thin films were annealed at 550 °C by changing the annealing time from 5 min to 30 min in a selenization furnace, using N2 as atmosphere. When the CuInSe2 thin films were annealed, without extra Se or H2Se gas used as the compensation source during the annealing process. The aim of this project was to investigate the influence of annealing time on the densification and crystallization of the CuInSe2 absorber layers to optimize the quality for cost effective solar cell production. The thickness of the CuInSe2 absorber layers could be controlled as the volume of used dispersed CuInSe2-isopropyl alcohol solution was controlled. In this work, X-ray diffraction patterns, field emission scanning electron microscopy, and Hall parameter measurements were performed in order to verify the quality of the CuInSe2 absorber layers obtained by the Spray Coating Method. PMID:28788451

Nonenzymatic detection of glucose using BaCuO2 thin layer

NASA Astrophysics Data System (ADS)

Ito, Takeshi; Asada, Tsuyoshi; Asai, Naoto; Shimizu, Tomohiro; Shingubara, Shoso

2017-01-01

A BaCuO2 thin layer was deposited on a glassy carbon electrode and used for the direct oxidation of glucose. The crystalline, electrochemical, and physicochemical properties that depend on the deposition temperature and deposition time were studied. X-ray diffraction (XRD) analysis showed that the thin layer was amorphous even at 400 °C. The current density of the glucose oxidation using the thin layer deposited at 200 °C was higher than those at other deposition temperatures. Under this condition, the current density increased with the glucose concentration and deposition time. These results indicate that a BaCuO2 thin layer has potential for measuring the blood glucose level without enzymes.

Fabrication and characterization of microstructures created in thermally deposited arsenic trisulfide by multiphoton lithography

NASA Astrophysics Data System (ADS)

Schwarz, Casey M.; Grabill, Chris N.; Richardson, Gerald D.; Labh, Shreya; Lewis, Anna M.; Vyas, Aadit; Gleason, Benn; Rivero-Baleine, Clara; Richardson, Kathleen A.; Pogrebnyakov, Alexej; Mayer, Theresa S.; Kuebler, Stephen M.

2017-04-01

A detailed study of multiphoton lithography (MPL) in arsenic trisulfide (As2S3) films and the effects on nanoscale morphology, chemical networking, and the appearance of the resulting features by the chemical composition, deposition rate, etch processing, and inclusion of an antireflection (AR) layer of As2Se3 between the substrate and the As2S3 layer is reported. MPL was used to photo-pattern nanostructured arrays in single- and multilayer films. The variation in chemical composition for laser-exposed, UV-exposed, and unexposed films is correlated with the etch response, nanostructure formation, and deposition conditions. Reflection of the focused beam at the substrate back into the film produces standing wave interference that modulates the exposure with distance from the substrate and produces nanobead structures. The interference and the modulation can be controlled by the addition of an AR layer of As2Se3 deposited between the substrate and the As2S3 film. Relative to structures produced in a single-layer As2S3 film having no AR layer, photo-patterning in the multilayer As2S3-on-As2Se3 film yields pillar-shaped structures that are closer to the targeted shape and are narrower (120 versus 320 nm), more uniform, and better adhering to the substrate. Processing methods are demonstrated for fabricating large-area arrays with diffractive optical function.

Topography evolution of rough-surface metallic substrates by solution deposition planarization method

NASA Astrophysics Data System (ADS)

Chu, Jingyuan; Zhao, Yue; Liu, Linfei; Wu, Wei; Zhang, Zhiwei; Hong, Zhiyong; Li, Yijie; Jin, Zhijian

2018-01-01

As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50 × 50 μm2 scanning scale) on both rough substrates reduced to ∼5 nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high Jc value of 4.17 MA cm-2 (at 77 K, s.f.) was achieved on a full stack of YBCO/CeO2/IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture.

Method for rapid, controllable growth and thickness, of epitaxial silicon films

DOEpatents

Wang, Qi [Littleton, CO; Stradins, Paul [Golden, CO; Teplin, Charles [Boulder, CO; Branz, Howard M [Boulder, CO

2009-10-13

A method of producing epitaxial silicon films on a c-Si wafer substrate using hot wire chemical vapor deposition by controlling the rate of silicon deposition in a temperature range that spans the transition from a monohydride to a hydrogen free silicon surface in a vacuum, to obtain phase-pure epitaxial silicon film of increased thickness is disclosed. The method includes placing a c-Si substrate in a HWCVD reactor chamber. The method also includes supplying a gas containing silicon at a sufficient rate into the reaction chamber to interact with the substrate to deposit a layer containing silicon thereon at a predefined growth rate to obtain phase-pure epitaxial silicon film of increased thickness.

Nano-scale zirconia and hafnia dielectrics grown by atomic layer deposition: Crystallinity, interface structures and electrical properties

NASA Astrophysics Data System (ADS)

Kim, Hyoungsub

With the continued scaling of transistors, leakage current densities across the SiO2 gate dielectric have increased enormously through direct tunneling. Presently, metal oxides having higher dielectric constants than SiO2 are being investigated to reduce the leakage current by increasing the physical thickness of the dielectric. Many possible techniques exist for depositing high-kappa gate dielectrics. Atomic layer deposition (ALD) has drawn attention as a method for preparing ultrathin metal oxide layers with excellent electrical characteristics and near-perfect film conformality due to the layer-by-layer nature of the deposition mechanism. For this research, an ALD system using ZrCl4/HfCl4 and H2O was built and optimized. The microstructural and electrical properties of ALD-ZrO2 and HfO2 grown on SiO2/Si substrates were investigated and compared using various characterization tools. In particular, the crystallization kinetics of amorphous ALD-HfO2 films were studied using in-situ annealing experiments in a TEM. The effect of crystallization on the electrical properties of ALD-HfO 2 was also investigated using various in-situ and ex-situ post-deposition anneals. Our results revealed that crystallization had little effect on the magnitude of the gate leakage current or on the conduction mechanisms. Building upon the results for each metal oxide separately, more advanced investigations were made. Several nanolaminate structures using ZrO2 and HfO2 with different sequences and layer thicknesses were characterized. The effects of the starting microstructure on the microstructural evolution of nanolaminate stacks were studied. Additionally, a promising new approach for engineering the thickness of the SiO2-based interface layer between the metal oxide and silicon substrate after deposition of the metal oxide layer was suggested. Through experimental measurements and thermodynamic analysis, it is shown that a Ti overlayer, which exhibits a high oxygen solubility, can effectively getter oxygen from the interface layer, thus decomposing SiO2 and reducing the interface layer thickness in a controllable fashion. As one of several possible applications, ALD-ZrO2 and HfO 2 gate dielectric films were deposited on Ge (001) substrates with different surface passivations. After extensive characterization using various microstructural, electrical, and chemical analyses, excellent MOS electrical properties of high-kappa gate dielectrics on Ge were successfully demonstrated with optimized surface nitridation of the Ge substrates.

Quantitative Super-Resolution Microscopy of Nanopipette-Deposited Fluorescent Patterns.

PubMed

Hennig, Simon; van de Linde, Sebastian; Bergmann, Stephan; Huser, Thomas; Sauer, Markus

2015-08-25

We describe a method for the deposition of minute amounts of fluorophore-labeled oligonucleotides with high local precision in conductive and transparent solid layers of poly(vinyl alcohol) (PVA) doped with glycerin and cysteamine (PVA-G-C layers). Deposition of negatively charged fluorescent molecules was accomplished with a setup based on a scanning ion conductance microscope (SICM) using nanopipettes with tip diameters of ∼100 nm by using the ion flux flowing between two electrodes through the nanopipette. To investigate the precision of the local deposition process, we performed in situ super-resolution microscopy by direct stochastic optical reconstruction microscopy (dSTORM). Exploiting the single-molecule sensitivity and reliability of dSTORM, we determine the number of fluorescent molecules deposited in single spots. The correlation of applied charge and number of deposited molecules enables the quantification of delivered molecules by measuring the charge during the delivery process. We demonstrate the reproducible deposition of 3-168 fluorescent molecules in single spots and the creation of fluorescent structures. The fluorescent structures are highly stable and can be reused several times.

Surface Passivation of ZrO2 Artificial Dentures by Magnetized Coaxial Plasma deposition

NASA Astrophysics Data System (ADS)

Arai, Soya; Kurumi, Satoshi; Matsuda, Ken-Ichi; Suzuki, Kaoru; Hara, Katsuya; Kato, Tatsuya; Asai, Tomohiko; Hirose, Hideharu; Masutani, Shigeyuki; Nihon University Team

2015-09-01

Recent growth and fabrication technologies for functional materials have been greatly contributed to drastic development of oral surgery field. Zirconia based ceramics is expected to utilize artificial dentures because these ceramics have good biocompatibility, high hardness and aesthetic attractively. However, to apply these ceramics to artificial dentures, this denture is removed from a dental plate because of weakly bond. For improving this problem, synthesis an Al passivation-layer on the ceramics for bonding with these dental items is suitable. In order to deposit the passivation layer, we focused on a magnetized coaxial plasma deposition (MCPD). The greatest characteristic of MCPD is that high-melting point metal can be deposited on various substrates. Additionally, adhesion force between substrate and films deposited by the MCPD is superior to it of general deposition methods. In this study, we have reported on the growth techniques of Al films on ZrO2 for contributing to oral surgery by the MCPD. Surface of deposited films shows there were some droplets and thickness of it is about 200 nm. Thickness is increased to 500 nm with increasing applied voltage.

Liftoff process for exfoliation of thin film photovoltaic devices and back contact formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haight, Richard A.; Hannon, James B.; Oida, Satoshi

A method for forming a back contact on an absorber layer in a photovoltaic device includes forming a two dimensional material on a first substrate. An absorber layer including Cu--Zn--Sn--S(Se) (CZTSSe) is grown over the first substrate on the two dimensional material. A buffer layer is grown on the absorber layer on a side opposite the two dimensional material. The absorber layer is exfoliated from the two dimensional material to remove the first substrate from a backside of the absorber layer opposite the buffer layer. A back contact is deposited on the absorber layer.

PLZT capacitor and method to increase the dielectric constant

DOEpatents

Taylor, Ralph S.; Fairchild, Manuel Ray; Balachjandran, Uthamalingam; Lee, Tae H.

2017-12-12

A ceramic-capacitor includes a first electrically-conductive-layer, a second electrically-conductive-layer arranged proximate to the first electrically-conductive-layer, and a dielectric-layer interposed between the first electrically-conductive-layer and the second electrically-conductive-layer. The dielectric-layer is formed of a lead-lanthanum-zirconium-titanate material (PLZT), wherein the PLZT is characterized by a dielectric-constant greater than 125, when measured at 25 degrees Celsius and zero Volts bias, and an excitation frequency of ten-thousand Hertz (10 kHz). A method for increasing a dielectric constant of the lead-lanthanum-zirconium-titanate material (PLZT) includes the steps of depositing PLZT to form a dielectric-layer of a ceramic-capacitor, and heating the ceramic-capacitor to a temperature not greater than 300.degree. C.

Fully integrated and encapsulated micro-fabricated vacuum diode and method of manufacturing same

DOEpatents

Resnick, Paul J.; Langlois, Eric

2015-12-01

Disclosed is an encapsulated micro-diode and a method for producing same. The method comprises forming a plurality columns in the substrate with a respective tip disposed at a first end of the column, the tip defining a cathode of the diode; disposing a sacrificial oxide layer on the substrate, plurality of columns and respective tips; forming respective trenches in the sacrificial oxide layer around the columns; forming an opening in the sacrificial oxide layer to expose a portion of the tips; depositing a conductive material in of the opening and on a surface of the substrate to form an anode of the diode; and removing the sacrificial oxide layer.

Method of manufacturing a fully integrated and encapsulated micro-fabricated vacuum diode

DOEpatents

Resnick, Paul J.; Langlois, Eric

2014-08-26

Disclosed is an encapsulated micro-diode and a method for producing same. The method comprises forming a plurality columns in the substrate with a respective tip disposed at a first end of the column, the tip defining a cathode of the diode; disposing a sacrificial oxide layer on the substrate, plurality of columns and respective tips; forming respective trenches in the sacrificial oxide layer around the columns; forming an opening in the sacrificial oxide layer to expose a portion of the tips; depositing a conductive material in of the opening and on a surface of the substrate to form an anode of the diode; and removing the sacrificial oxide layer.

Tsunami Evidence in South Coast Java, Case Study: Tsunami Deposit along South Coast of Cilacap

NASA Astrophysics Data System (ADS)

Rizal, Yan; Aswan; Zaim, Yahdi; Dwijo Santoso, Wahyu; Rochim, Nur; Daryono; Dewi Anugrah, Suci; Wijayanto; Gunawan, Indra; Yatimantoro, Tatok; Hidayanti; Herdiyani Rahayu, Resti; Priyobudi

2017-06-01

Cilacap Area is situated in coastal area of Southern Java and directly affected by tsunami hazard in 2006. This event was triggered by active subduction in Java Trench which active since long time ago. To detect tsunami and active tectonic in Southern Java, paleo-tsunami study is performed which is targeted paleo-tsunami deposit older than fifty years ago. During 2011 - 2016, 16 locations which suspected as paleo-tsunami location were visited and the test-pits were performed to obtain characteristic and stratigraphy of paleo-tsunami layers. Paleo-tsunami layer was identified by the presence of light-sand in the upper part of paleo-soil, liquefaction fine grain sandstone, and many rip-up clast of mudstone. The systematic samples were taken and analysis (micro-fauna, grainsize and dating analysis). Micro-fauna result shows that paleo-tsunami layer consist of benthonic foraminifera assemblages from different bathymetry and mixing in one layer. Moreover, grainsize shows random grain distribution which characterized as turbulence and strong wave deposit. Paleo-tsunami layers in Cilacap area are correlated using paleo-soil as marker. There are three paleo-tsunami layers and the distribution can be identified as PS-A, PS-B and PS-C. The samples which were taken in Glempang Pasir layer are being dated using Pb - Zn (Lead-Zinc) method. The result of Pb - Zn (Lead-Zinc) dating shows that PS-A was deposited in 139 years ago, PS-B in 21 years ago, and PS C in 10 years ago. This result indicates that PS -1 occurred in 1883 earthquake activity while PS B formed in 1982 earthquake and PS-C was formed by 2006 earthquake. For ongoing research, the older paleo-tsunami layers were determined in the Gua Nagaraja, close to Selok location and 6 layers of Paleo-tsunami suspect found which shown a similar characteristic with the layers from another location. The three layers deeper approximately have an older age than another location in Cilacap.

Method and apparatus for rapid biohydrogen phenotypic screening of microorganisms using a chemochromic sensor

DOEpatents

Seibert, Michael; Benson, David K.; Flynn, Timothy Michael

2001-01-01

The invention provides an assay system for identifying a hydrogen-gas-producing organism, including a sensor film having a first layer comprising a transition metal oxide or oxysalt and a second layer comprising hydrogen-dissociative catalyst metal, the first and second layers having an inner and an outer surface wherein the inner surface of the second layer is deposited on the outer surface of the first layer, and a substrate disposed proximally to the outer surface of the second layer, the organism being isolated on the substrate.

Buffer layers for REBCO films for use in superconducting devices

DOEpatents

Goyal, Amit; Wee, Sung-Hun

2014-06-10

A superconducting article includes a substrate having a biaxially textured surface. A biaxially textured buffer layer, which can be a cap layer, is supported by the substrate. The buffer layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different transition metal cations. A biaxially textured superconductor layer is deposited so as to be supported by the buffer layer. A method of making a superconducting article is also disclosed.

Method and apparatus for the evaluation of a depth profile of thermo-mechanical properties of layered and graded materials and coatings

DOEpatents

Finot, Marc; Kesler, Olivera; Suresh, Subra

1998-01-01

A technique for determining properties such as Young's modulus, coefficient of thermal expansion, and residual stress of individual layers within a multi-layered sample is presented. The technique involves preparation of a series of samples, each including one additional layer relative to the preceding sample. By comparison of each sample to a preceding sample, properties of the topmost layer can be determined, and residual stress at any depth in each sample, resulting from deposition of the top layer, can be determined.

Effects of Additives on Electrochemical Growth of Cu Film on Co/SiO2/Si Substrate by Alternating Underpotential Deposition of Pb and Surface-Limited Redox Replacement by Cu

NASA Astrophysics Data System (ADS)

Fang, J. S.; Lin, L. Y.; Wu, C. L.; Cheng, Y. L.; Chen, G. S.

2017-11-01

The effects of additives to an acidic electrolyte for electrochemical deposition of copper film to prevent corrosion of the Co/SiO2/Si substrate have been investigated. A sacrificial Pb layer was formed by underpotential deposition (UPD), then a Cu layer was prepared using surface-limited redox replacement (SLRR) to exchange the UPD-Pb layer in an acidic copper electrolyte with trisodium citrate, sodium perchlorate, and ethylenediamine as additives. The additives significantly affected the replacement of UPD-Pb by Cu and prevented galvanic corrosion of the Co/SiO2/Si substrate in the acidic Cu electrolyte. The results showed that both sodium perchlorate and ethylenediamine reduced the corrosion of the Co substrate and resulted in Cu film with low electrical resistivity. However, residual Pb was present in the Cu film when using trisodium citrate, as the citrate ions slowed copper displacement. The proposed sequential UPD-Pb and SLRR-Cu growth method may enable electrochemical deposition for fabrication of Cu interconnects on Co substrate from acidic Cu electrolyte.

A new CT scan methodology to characterize a small aggregation gravel clast contained in a soft sediment matrix

NASA Astrophysics Data System (ADS)

Fouinat, Laurent; Sabatier, Pierre; Poulenard, Jérôme; Reyss, Jean-Louis; Montet, Xavier; Arnaud, Fabien

2017-03-01

Over the past decades, X-ray computed tomography (CT) has been increasingly applied in the geosciences community. CT scanning is a rapid, non-destructive method allowing the assessment of relative density of clasts in natural archives samples. This study focuses on the use of this method to explore instantaneous deposits as major contributors to sedimentation of high-elevation lakes in the Alps, such as the Lake Lauvitel system (western French Alps). This lake is located within a very steep valley prone to episodic flooding and features gullies ending in the lake. This variety of erosion processes leads to deposition of sedimentary layers with distinct clastic properties. We identified 18 turbidites and 15 layers of poorly sorted fine sediment associated with the presence of gravels since AD 1880. These deposits are respectively interpreted as being induced by flood and wet avalanche. This constitutes a valuable record from a region where few historical records exist. This CT scan approach is suitable for instantaneous deposit identification to reconstruct past evolution and may be applicable to a wider variety of sedimentary archives alongside existing approaches.

Atomic layer deposition and etching methods for far ultraviolet aluminum mirrors

NASA Astrophysics Data System (ADS)

Hennessy, John; Moore, Christopher S.; Balasubramanian, Kunjithapatham; Jewell, April D.; Carter, Christian; France, Kevin; Nikzad, Shouleh

2017-09-01

High-performance aluminum mirrors at far ultraviolet wavelengths require transparent dielectric materials as protective coatings to prevent oxidation. Reducing the thickness of this protective layer can result in additional performance gains by minimizing absorption losses, and provides a path toward high Al reflectance in the challenging wavelength range of 90 to 110 nm. We have pursued the development of new atomic layer deposition processes (ALD) for the metal fluoride materials of MgF2, AlF3 and LiF. Using anhydrous hydrogen fluoride as a reactant, these films can be deposited at the low temperatures required for large-area surface-finished optics and polymeric diffraction gratings. We also report on the development and application of an atomic layer etching (ALE) procedure to controllably etch native aluminum oxide. Our ALE process utilizes the same chemistry used in the ALD of AlF3 thin films, allowing for a combination of high-performance evaporated Al layers and ultrathin ALD encapsulation without requiring vacuum transfer. Progress in demonstrating the scalability of this approach, as well as the environmental stability of ALD/ALE Al mirrors are discussed in the context of possible future applications for NASA LUVOIR and HabEx mission concepts.

Effect of precursor concentration and film thickness deposited by layer on nanostructured TiO2 thin films

NASA Astrophysics Data System (ADS)

Affendi, I. H. H.; Sarah, M. S. P.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

2018-05-01

Sol-gel spin coating method is used in the production of nanostructured TiO2 thin film. The surface topology and morphology was observed using the Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The electrical properties were investigated by using two probe current-voltage (I-V) measurements to study the electrical resistivity behavior, hence the conductivity of the thin film. The solution concentration will be varied from 14.0 to 0.01wt% with 0.02wt% interval where the last concentration of 0.02 to 0.01wt% have 0.01wt% interval to find which concentrations have the highest conductivity then the optimized concentration's sample were chosen for the thickness parameter based on layer by layer deposition from 1 to 6 layer. Based on the result, the lowest concentration of TiO2, the surface becomes more uniform and the conductivity will increase. As the result, sample of 0.01wt% concentration have conductivity value of 1.77E-10 S/m and will be advanced in thickness parameter. Whereas in thickness parameter, the 3layer deposition were chosen as its conductivity is the highest at 3.9098E9 S/m.

CMUTs with high-K atomic layer deposition dielectric material insulation layer.

PubMed

Xu, Toby; Tekes, Coskun; Degertekin, F

2014-12-01

Use of high-κ dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (Six)Ny)) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2) such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD Six)Ny) and 100-nm HfO2) insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure.

75 FR 14628 - Notice of Commission Decision

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-26

... complete, third recited step of claim 1, i.e., ``depositing a tungsten layer by chemical vapor deposition, said tungsten layer covering said glue layer on said dielectric and said exposed material.'' The... to the third step only includes the step of ``depositing a tungsten layer by chemical vapor...

Aqueous Solution-Phase Selenized CuIn(S,Se)2 Thin Film Solar Cells Annealed under Inert Atmosphere.

PubMed

Oh, Yunjung; Yang, Wooseok; Kim, Jimin; Woo, Kyoohee; Moon, Jooho

2015-10-14

A nonvacuum solution-based approach can potentially be used to realize low cost, roll-to-roll fabrication of chalcopyrite CuIn(S,Se)2 (CISSe) thin film solar cells. However, most solution-based fabrication methods involve highly toxic solvents and inevitably require sulfurization and/or postselenization with hazardous H2S/H2Se gases. Herein, we introduce novel aqueous-based Cu-In-S and Se inks that contain an amine additive for producing a high-quality absorber layer. CISSe films were fabricated by simple deposition of Cu-In-S ink and Se ink followed by annealing under an inert atmosphere. Compositional and phase analyses confirmed that our simple aqueous ink-based method facilitated in-site selenization of the CIS layer. In addition, we investigated the molecular structures of our aqueous inks to determine how crystalline chalcopyrite absorber layers developed without sulfurization and/or postselenization. CISSe thin film solar cells annealed at 550 °C exhibited an efficiency of 4.55% under AM 1.5 illumination. The low-cost, nonvacuum method to deposit chalcopyrite absorber layers described here allows for safe and simple processing of thin film solar cells.

Structure and enhanced thermochromic performance of low-temperature fabricated VO2/V2O3 thin film

NASA Astrophysics Data System (ADS)

Sun, Guangyao; Cao, Xun; Gao, Xiang; Long, Shiwei; Liang, Mengshi; Jin, Ping

2016-10-01

For VO2-based smart window manufacture, it is a long-standing demand for high-quality thin films deposited at low temperature. Here, the thermochromic films of VO2 were deposited by a magnetron sputtering method at a fairly low temperature of 250 °C without subsequent annealing by embedding a V2O3 interlayer. V2O3 acts as a seed layer to lower the depositing temperature and buffer layer to epitaxial grow VO2 film. The VO2/V2O3 films display high solar modulating ability and narrow hysteresis loop. Our data can serve as a promising point for industrial production with high degree of crystallinity at a low temperature.

Flower-like ZnO nanorod arrays grown on HF-etched Si (111): constraining relation between ZnO seed layer and Si (111)

NASA Astrophysics Data System (ADS)

Brahma, Sanjaya; Liu, C.-W.; Huang, R.-J.; Chang, S.-J.; Lo, K.-Y.

2015-11-01

We demonstrate the formation of self-assembled homogenous flower-like ZnO nanorods over a ZnO seed layer deposited on a HF-etched Si (111) substrate. The typical flower-like morphology of ZnO nanorod arrays is ascribed to the formation of the island-like seed layer which is deposited by the drop method followed by annealing at 300 °C. The island-like ZnO seed layer consists of larger ZnO grains, and is built by constraining of the Si (111) surface due to pattern matching. Pattern matching of Si with ZnO determines the shape and size of the seed layer and this controls the final morphology of ZnO nanorods to be either flower like or vertically aligned. The high quality of the island-like ZnO seed layer enhances the diameter and length of ZnO nanorods. Besides, while the amorphous layer formed during the annealing process would influence the strained ZnO grain, that subsequent amorphous layer will not block the constraining between the ZnO grain and the substrate.

Method for reducing or eliminating interface defects in mismatched semiconductor epilayers

DOEpatents

Fitzgerald, Jr., Eugene A.; Ast, Dieter G.

1992-01-01

The present invention and process relates to crystal lattice mismatched semiconductor composite having a first semiconductor layer and a second semiconductor growth layer deposited thereon to form an interface wherein the growth layer can be deposited at thicknesses in excess of the critical thickness, even up to about 10.times. critical thickness. Such composite has an interface which is substantially free of interface defects. For example, the size of the growth areas in a mismatched In.sub.0.05 Ga.sub.0.95 As/(001)GaAs interface was controlled by fabricating 2-.mu.m high pillars of various lateral geometries and lateral dimensions before the epitaxial deposition of 3500.ANG. of In.sub.0.05 Ga.sub.0.95 As. The linear dislocation density at the interface was reduced from >5000 dislocations/cm to about zero for 25-.mu.m lateral dimensions and to less than 800 dislocations/cm for lateral dimensions as large as 100 .mu.m. The fabricated pillars control the lateral dimensions of the growth layer and block the glide of misfit dislocations with the resultant decrease in dislocation density.

Method for reducing or eliminating interface defects in mismatched semiconductor eiplayers

DOEpatents

Fitzgerald, Jr., Eugene A.; Ast, Dieter G.

1991-01-01

The present invention and process relates to crystal lattice mismatched semiconductor composite having a first semiconductor layer and a second semiconductor growth layer deposited thereon to form an interface wherein the growth layer can be deposited at thicknesses in excess of the critical thickness, even up to about 10x critical thickness. Such composite has an interface which is substantially free of interface defects. For example, the size of the growth areas in a mismatched In.sub.0.05 Ga.sub.0.95 As/(001)GaAs interface was controlled by fabricating 2-.mu.m high pillars of various lateral geometries and lateral dimensions before the epitaxial deposition of 3500.ANG. of In.sub.0.05 Ga.sub.0.95 As. The linear dislocation density at the interface was reduced from >5000 dislocations/cm to about zero for 25-.mu.m lateral dimensions and to less than 800 dislocations/cm for lateral dimensions as large as 100 .mu.m. The fabricated pillars control the lateral dimensions of the growth layer and block the glide of misfit dislocations with the resultant decrease in dislocation density.

Method for reducing or eliminating interface defects in mismatched semiconductor epilayers

DOEpatents

Fitzgerald, E.A. Jr.; Ast, D.G.

1992-10-20

The present invention and process relates to crystal lattice mismatched semiconductor composite having a first semiconductor layer and a second semiconductor growth layer deposited thereon to form an interface wherein the growth layer can be deposited at thicknesses in excess of the critical thickness, even up to about 10[times] critical thickness. Such composite has an interface which is substantially free of interface defects. For example, the size of the growth areas in a mismatched In[sub 0.05]Ga[sub 0.95]As/(001)GaAs interface was controlled by fabricating 2-[mu]m high pillars of various lateral geometries and lateral dimensions before the epitaxial deposition of 3500 [angstrom] of In[sub 0.05]Ga[sub 0.95]As. The linear dislocation density at the interface was reduced from >5000 dislocations/cm to about zero for 25-[mu]m lateral dimensions and to less than 800 dislocations/cm for lateral dimensions as large as 100 [mu]m. The fabricated pillars control the lateral dimensions of the growth layer and block the glide of misfit dislocations with the resultant decrease in dislocation density. 7 figs.

High performance thin film transistor with ZnO channel layer deposited by DC magnetron sputtering.

PubMed

Moon, Yeon-Keon; Moon, Dae-Yong; Lee, Sang-Ho; Jeong, Chang-Oh; Park, Jong-Wan

2008-09-01

Research in large area electronics, especially for low-temperature plastic substrates, focuses commonly on limitations of the semiconductor in thin film transistors (TFTs), in particular its low mobility. ZnO is an emerging example of a semiconductor material for TFTs that can have high mobility, while a-Si and organic semiconductors have low mobility (<1 cm2/Vs). ZnO-based TFTs have achieved high mobility, along with low-voltage operation low off-state current, and low gate leakage current. In general, ZnO thin films for the channel layer of TFTs are deposited with RF magnetron sputtering methods. On the other hand, we studied ZnO thin films deposited with DC magnetron sputtering for the channel layer of TFTs. After analyzing the basic physical and chemical properties of ZnO thin films, we fabricated a TFT-unit cell using ZnO thin films for the channel layer. The field effect mobility (micro(sat)) of 1.8 cm2/Vs and threshold voltage (Vth) of -0.7 V were obtained.

Layer-by-layer assembly of TiO(2) colloids onto diatomite to build hierarchical porous materials.

PubMed

Jia, Yuxin; Han, Wei; Xiong, Guoxing; Yang, Weishen

2008-07-15

TiO(2) colloids with the most probably particle size of 10 nm were deposited on the surface of macroporous diatomite by a layer-by-layer (LBL) assembly method with using phytic acid as molecular binder. For preparation of colloidal TiO(2), titanium(IV) isopropoxide (Ti(C(3)H(7)O)(4)) was used as titanium precursor, nitric acid (HNO(3)) as peptizing agent and deionized water and isopropanol (C(3)H(7)OH) as solvent. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N(2) adsorption-desorption, and UV-vis spectra are used to assess the morphology and physical chemistry properties of the resulting TiO(2) coated diatomite. It was shown that the mesoporosity has been introduced into macroporous diatomite by LBL deposition. The mesoporosity was originated from close-packing of the uniform TiO(2) nanoparticles. More TiO(2) could be coated on the surface of diatomite by increasing the deposition cycles. This hierarchical porous material has potential for applications in catalytic reactions involved diffusion limit, especially in photocatalytic reactions.

Formation of charge-nanopatterned templates with flexible geometry via layer by layer deposition of polyelectrolytes for directed self-assembly of gold nanoparticles

NASA Astrophysics Data System (ADS)

Sayin, Mustafa; Dahint, Reiner

2017-03-01

Nanostructure formation via self-assembly processes offers a fast and cost-effective approach to generate surface patterns on large lateral scale. In particular, if the high precision of lithographic techniques is not required, a situation typical of many biotechnological and biomedical applications, it may be considered as the method of choice as it does not require any sophisticated instrumentation. However, in many cases the variety and complexity of the surface structures accessible with a single self-assembly based technique is limited. Here, we report on a new approach which combines two different self-assembly strategies, colloidal lithography and layer-by-layer deposition of polyelectrolytes, in order to significantly expand the spectrum of accessible patterns. In particular, flat and donut-like charge-patterned templates have been generated, which facilitate subsequent deposition of gold nanoparticles in dot, grid, ring, out-of-ring and circular patch structures. Potential applications are e.g. in the fields of biofunctional interfaces with well-defined lateral dimensions, optical devices with tuned properties, and controlled three-dimensional material growth.

Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process

PubMed Central

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-01-01

This study proposes a two-photomask process for fabricating amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity. PMID:28788026

Enhancement of the conductivity of nanomaterial layers by laser irradiation

NASA Astrophysics Data System (ADS)

Ichkitidze, Levan P.; Glukhova, Olga E.; Savostyanov, Georgy V.; Gerasimenko, Alexander Yu.; Podgaetsky, Vitaly M.; Selishchev, Sergey V.; Zhurbina, Natalia N.

2017-07-01

The conductivity of layers (thickness 0.5 ÷ 50 μm) of composite nanomaterials consisting of bovine serum albumin (BSA) with single-walled carbon nanotubes (SWCNTs) has been studied. The aqueous dispersion of BSA / SWCNT was deposited on different substrates using the silk screening method. Conductivity was increased (30 ÷ 700) % by laser irradiation of the layers when they were in the liquid state. The investigated layers are promising for use in medical practice.

Stratigraphy and erosional landforms of layered deposits in Valles Marineris, Mars

NASA Technical Reports Server (NTRS)

Komatsu, G.; Geissler, P. E.; Strom, R. G.; Singer, R. B.

1993-01-01

Satellite imagery is used to identify stratigraphy and erosional landforms of 13 layered deposits in the Valles Marineris region of Mars (occurring, specifically, in Gangis, Juventae, Hebes, Ophir-Candor, Melas, and Capri-Eos Chasmata), based on albedo and erosional styles. Results of stratigraphic correlations show that the stratigraphy of layered deposits in the Hebes, Juventae, and Gangis Chasmata are not well correlated, indicating that at least these chasmata had isolated depositional environments resulting in different stratigraphic sequences. On the other hand, the layered deposits in Ophir-Candor and Melas Chasmata appear to have been connected in each chasma. Some of the layered deposits display complexities which indicate changes in space and time in the dominant source materials.

Method for producing high quality oxide films on substrates

DOEpatents

Ruckman, Mark W.; Strongin, Myron; Gao, Yong L.

1993-01-01

A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.